diff --git a/tools/interop_matrix/client_matrix.py b/tools/interop_matrix/client_matrix.py
index 131c4a789e2..51f04ea40b1 100644
--- a/tools/interop_matrix/client_matrix.py
+++ b/tools/interop_matrix/client_matrix.py
@@ -97,7 +97,7 @@ LANG_RELEASE_MATRIX = {
         'v1.6.6',
     ],
    'csharp': [
-        # Fail to build docker image with v1.3.9 and earlier.
+        # Fail to build images due to #13278.
         #'v1.0.1',
         #'v1.1.4',
         #'v1.2.5',
diff --git a/tools/interop_matrix/create_matrix_images.py b/tools/interop_matrix/create_matrix_images.py
index 86c5bf45d7d..21040eadf25 100755
--- a/tools/interop_matrix/create_matrix_images.py
+++ b/tools/interop_matrix/create_matrix_images.py
@@ -227,7 +227,6 @@ def checkout_grpc_stack(lang, release):
   repo_dir = os.path.splitext(os.path.basename(repo))[0]
   stack_base = os.path.join(args.git_checkout_root, repo_dir)
 
-  # Assume the directory is reusable for git checkout.
   if not os.path.exists(stack_base):
     subprocess.check_call(['git', 'clone', '--recursive', repo],
                           cwd=os.path.dirname(stack_base))
@@ -240,7 +239,9 @@ def checkout_grpc_stack(lang, release):
   output = subprocess.check_output(
       ['git', 'checkout', release], cwd=stack_base, stderr=subprocess.STDOUT)
   commit_log = subprocess.check_output(['git', 'log', '-1'], cwd=stack_base)
-  jobset.message('SUCCESS', 'git checkout', output + commit_log, do_newline=True)
+  jobset.message('SUCCESS', 'git checkout', 
+                 '%s: %s' % (str(output), commit_log), 
+                 do_newline=True)
 
   # Write git log to commit_log so it can be packaged with the docker image.
   with open(os.path.join(stack_base, 'commit_log'), 'w') as f:
diff --git a/tools/interop_matrix/create_testcases.sh b/tools/interop_matrix/create_testcases.sh
index 2ea2d3ad908..fa33fa4615f 100755
--- a/tools/interop_matrix/create_testcases.sh
+++ b/tools/interop_matrix/create_testcases.sh
@@ -31,18 +31,6 @@ TESTCASES_DIR=${GRPC_ROOT}/tools/interop_matrix/testcases
 
 echo "Create '$LANG' test cases for gRPC release '${RELEASE:=master}'"
 
-# Invoke run_interop_test in manual mode.
-# TODO(adelez): Add cloud_gateways when we figure out how to skip them if not 
-# running in GCE.
-if [ $LANG == "cxx" ]; then
-client_lang="c++"
-else
-client_lang=$LANG
-fi
-echo $client_lang
-${GRPC_ROOT}/tools/run_tests/run_interop_tests.py -l $client_lang --use_docker \
-  --cloud_to_prod --prod_servers default gateway_v4 --manual_run
-
 # Clean up
 function cleanup {
   [ -z "$testcase" ] && testcase=$CMDS_SH
@@ -59,13 +47,28 @@ function cleanup {
   fi
   [ -e "$CMDS_SH" ] && rm $CMDS_SH
 }
+
+function createtests {
+# Invoke run_interop_test in manual mode.
+# TODO(adelez): Add cloud_gateways when we figure out how to skip them if not 
+# running in GCE.
+if [ $1 == "cxx" ]; then
+client_lang="c++"
+else
+client_lang=$1
+fi
+echo $client_lang
+
+${GRPC_ROOT}/tools/run_tests/run_interop_tests.py -l $client_lang --use_docker \
+  --cloud_to_prod --prod_servers default gateway_v4 --manual_run
+
 trap cleanup EXIT
 # TODO(adelez): add test auth tests but do not run if not testing on GCE.
 # Running the testcases as sanity unless we are asked to skip.
 [ -z "$SKIP_TEST" ] && (echo "Running test cases: $CMDS_SH"; sh $CMDS_SH)
 
 mkdir -p $TESTCASES_DIR
-testcase=$TESTCASES_DIR/${LANG}__$RELEASE
+testcase=$TESTCASES_DIR/$1__$RELEASE
 if [ -e $testcase ]; then
   echo "Updating: $testcase"
   diff $testcase $CMDS_SH || true
@@ -73,3 +76,11 @@ fi
 mv $CMDS_SH $testcase
 chmod a+x $testcase
 echo "Test cases created: $testcase"
+}
+
+if [ $LANG == "csharp" ]; then
+createtests "csharp"
+createtests "csharpcoreclr"
+else
+createtests $LANG
+fi 
diff --git a/tools/interop_matrix/run_interop_matrix_tests.py b/tools/interop_matrix/run_interop_matrix_tests.py
index bb7a8647c7c..491438a2921 100755
--- a/tools/interop_matrix/run_interop_matrix_tests.py
+++ b/tools/interop_matrix/run_interop_matrix_tests.py
@@ -122,13 +122,16 @@ def find_all_images_for_lang(lang):
   return images
 
 # caches test cases (list of JobSpec) loaded from file.  Keyed by lang and runtime.
-def find_test_cases(lang, release, suite_name):
+def find_test_cases(lang, runtime, release, suite_name):
   """Returns the list of test cases from testcase files per lang/release."""
   file_tmpl = os.path.join(os.path.dirname(__file__), 'testcases/%s__%s')
   testcase_release = release
-  if not os.path.exists(file_tmpl % (lang, release)):
+  filename_prefix = lang
+  if lang == 'csharp':
+    filename_prefix = runtime
+  if not os.path.exists(file_tmpl % (filename_prefix, release)):
     testcase_release = 'master'
-  testcases = file_tmpl % (lang, testcase_release)
+  testcases = file_tmpl % (filename_prefix, testcase_release)
 
   job_spec_list=[]
   try:
@@ -169,7 +172,12 @@ def run_tests_for_lang(lang, runtime, images):
     subprocess.check_call(['gcloud', 'docker', '--', 'pull', image])
     _docker_images_cleanup.append(image)
     suite_name = '%s__%s_%s' % (lang, runtime, release)
-    job_spec_list = find_test_cases(lang, release, suite_name)
+    job_spec_list = find_test_cases(lang, runtime, release, suite_name)
+    
+    if not job_spec_list:  
+      jobset.message('FAILED', 'No test cases were found.', do_newline=True)
+      return 1
+
     num_failures, resultset = jobset.run(job_spec_list,
                                          newline_on_success=True,
                                          add_env={'docker_image':image},
diff --git a/tools/interop_matrix/testcases/csharp__master b/tools/interop_matrix/testcases/csharp__master
old mode 100755
new mode 100644
diff --git a/tools/interop_matrix/testcases/csharpcoreclr__master b/tools/interop_matrix/testcases/csharpcoreclr__master
new file mode 100644
index 00000000000..37e45989b2e
--- /dev/null
+++ b/tools/interop_matrix/testcases/csharpcoreclr__master
@@ -0,0 +1,20 @@
+#!/bin/bash
+echo "Testing ${docker_image:=grpc_interop_csharpcoreclr:c7fbed09-e4c1-4aab-8dd9-1285b2c9598e}"
+docker run -i --rm=true -w /var/local/git/grpc/src/csharp/Grpc.IntegrationTesting.Client/bin/Debug/netcoreapp1.0 --net=host $docker_image bash -c "dotnet exec Grpc.IntegrationTesting.Client.dll --server_host=216.239.32.254 --server_host_override=grpc-test.sandbox.googleapis.com --server_port=443 --use_tls=true --test_case=large_unary"
+docker run -i --rm=true -w /var/local/git/grpc/src/csharp/Grpc.IntegrationTesting.Client/bin/Debug/netcoreapp1.0 --net=host $docker_image bash -c "dotnet exec Grpc.IntegrationTesting.Client.dll --server_host=216.239.32.254 --server_host_override=grpc-test.sandbox.googleapis.com --server_port=443 --use_tls=true --test_case=empty_unary"
+docker run -i --rm=true -w /var/local/git/grpc/src/csharp/Grpc.IntegrationTesting.Client/bin/Debug/netcoreapp1.0 --net=host $docker_image bash -c "dotnet exec Grpc.IntegrationTesting.Client.dll --server_host=216.239.32.254 --server_host_override=grpc-test.sandbox.googleapis.com --server_port=443 --use_tls=true --test_case=ping_pong"
+docker run -i --rm=true -w /var/local/git/grpc/src/csharp/Grpc.IntegrationTesting.Client/bin/Debug/netcoreapp1.0 --net=host $docker_image bash -c "dotnet exec Grpc.IntegrationTesting.Client.dll --server_host=216.239.32.254 --server_host_override=grpc-test.sandbox.googleapis.com --server_port=443 --use_tls=true --test_case=empty_stream"
+docker run -i --rm=true -w /var/local/git/grpc/src/csharp/Grpc.IntegrationTesting.Client/bin/Debug/netcoreapp1.0 --net=host $docker_image bash -c "dotnet exec Grpc.IntegrationTesting.Client.dll --server_host=216.239.32.254 --server_host_override=grpc-test.sandbox.googleapis.com --server_port=443 --use_tls=true --test_case=client_streaming"
+docker run -i --rm=true -w /var/local/git/grpc/src/csharp/Grpc.IntegrationTesting.Client/bin/Debug/netcoreapp1.0 --net=host $docker_image bash -c "dotnet exec Grpc.IntegrationTesting.Client.dll --server_host=216.239.32.254 --server_host_override=grpc-test.sandbox.googleapis.com --server_port=443 --use_tls=true --test_case=server_streaming"
+docker run -i --rm=true -w /var/local/git/grpc/src/csharp/Grpc.IntegrationTesting.Client/bin/Debug/netcoreapp1.0 --net=host $docker_image bash -c "dotnet exec Grpc.IntegrationTesting.Client.dll --server_host=216.239.32.254 --server_host_override=grpc-test.sandbox.googleapis.com --server_port=443 --use_tls=true --test_case=cancel_after_begin"
+docker run -i --rm=true -w /var/local/git/grpc/src/csharp/Grpc.IntegrationTesting.Client/bin/Debug/netcoreapp1.0 --net=host $docker_image bash -c "dotnet exec Grpc.IntegrationTesting.Client.dll --server_host=216.239.32.254 --server_host_override=grpc-test.sandbox.googleapis.com --server_port=443 --use_tls=true --test_case=cancel_after_first_response"
+docker run -i --rm=true -w /var/local/git/grpc/src/csharp/Grpc.IntegrationTesting.Client/bin/Debug/netcoreapp1.0 --net=host $docker_image bash -c "dotnet exec Grpc.IntegrationTesting.Client.dll --server_host=216.239.32.254 --server_host_override=grpc-test.sandbox.googleapis.com --server_port=443 --use_tls=true --test_case=timeout_on_sleeping_server"
+docker run -i --rm=true -w /var/local/git/grpc/src/csharp/Grpc.IntegrationTesting.Client/bin/Debug/netcoreapp1.0 --net=host $docker_image bash -c "dotnet exec Grpc.IntegrationTesting.Client.dll --server_host=216.239.32.254 --server_host_override=grpc-test4.sandbox.googleapis.com --server_port=443 --use_tls=true --test_case=large_unary"
+docker run -i --rm=true -w /var/local/git/grpc/src/csharp/Grpc.IntegrationTesting.Client/bin/Debug/netcoreapp1.0 --net=host $docker_image bash -c "dotnet exec Grpc.IntegrationTesting.Client.dll --server_host=216.239.32.254 --server_host_override=grpc-test4.sandbox.googleapis.com --server_port=443 --use_tls=true --test_case=empty_unary"
+docker run -i --rm=true -w /var/local/git/grpc/src/csharp/Grpc.IntegrationTesting.Client/bin/Debug/netcoreapp1.0 --net=host $docker_image bash -c "dotnet exec Grpc.IntegrationTesting.Client.dll --server_host=216.239.32.254 --server_host_override=grpc-test4.sandbox.googleapis.com --server_port=443 --use_tls=true --test_case=ping_pong"
+docker run -i --rm=true -w /var/local/git/grpc/src/csharp/Grpc.IntegrationTesting.Client/bin/Debug/netcoreapp1.0 --net=host $docker_image bash -c "dotnet exec Grpc.IntegrationTesting.Client.dll --server_host=216.239.32.254 --server_host_override=grpc-test4.sandbox.googleapis.com --server_port=443 --use_tls=true --test_case=empty_stream"
+docker run -i --rm=true -w /var/local/git/grpc/src/csharp/Grpc.IntegrationTesting.Client/bin/Debug/netcoreapp1.0 --net=host $docker_image bash -c "dotnet exec Grpc.IntegrationTesting.Client.dll --server_host=216.239.32.254 --server_host_override=grpc-test4.sandbox.googleapis.com --server_port=443 --use_tls=true --test_case=client_streaming"
+docker run -i --rm=true -w /var/local/git/grpc/src/csharp/Grpc.IntegrationTesting.Client/bin/Debug/netcoreapp1.0 --net=host $docker_image bash -c "dotnet exec Grpc.IntegrationTesting.Client.dll --server_host=216.239.32.254 --server_host_override=grpc-test4.sandbox.googleapis.com --server_port=443 --use_tls=true --test_case=server_streaming"
+docker run -i --rm=true -w /var/local/git/grpc/src/csharp/Grpc.IntegrationTesting.Client/bin/Debug/netcoreapp1.0 --net=host $docker_image bash -c "dotnet exec Grpc.IntegrationTesting.Client.dll --server_host=216.239.32.254 --server_host_override=grpc-test4.sandbox.googleapis.com --server_port=443 --use_tls=true --test_case=cancel_after_begin"
+docker run -i --rm=true -w /var/local/git/grpc/src/csharp/Grpc.IntegrationTesting.Client/bin/Debug/netcoreapp1.0 --net=host $docker_image bash -c "dotnet exec Grpc.IntegrationTesting.Client.dll --server_host=216.239.32.254 --server_host_override=grpc-test4.sandbox.googleapis.com --server_port=443 --use_tls=true --test_case=cancel_after_first_response"
+docker run -i --rm=true -w /var/local/git/grpc/src/csharp/Grpc.IntegrationTesting.Client/bin/Debug/netcoreapp1.0 --net=host $docker_image bash -c "dotnet exec Grpc.IntegrationTesting.Client.dll --server_host=216.239.32.254 --server_host_override=grpc-test4.sandbox.googleapis.com --server_port=443 --use_tls=true --test_case=timeout_on_sleeping_server"