diff --git a/.gitignore b/.gitignore
index 3e40963ee..2373d5dc7 100644
--- a/.gitignore
+++ b/.gitignore
@@ -8,6 +8,7 @@
 .coverage
 .coverage.*
 coverage.xml
+coverage.json
 .metacov
 .metacov.*
 *.swp
diff --git a/Makefile b/Makefile
index b1cc84968..909ca4d6e 100644
--- a/Makefile
+++ b/Makefile
@@ -22,7 +22,7 @@ clean: clean_platform                   ## Remove artifacts of test execution, i
 	@rm -f *$$py.class */*$$py.class */*/*$$py.class */*/*/*$$py.class */*/*/*/*$$py.class */*/*/*/*/*$$py.class
 	@rm -f coverage/*,cover
 	@rm -f MANIFEST
-	@rm -f .coverage .coverage.* coverage.xml .metacov*
+	@rm -f .coverage .coverage.* coverage.xml coverage.json .metacov*
 	@rm -f .tox/*/lib/*/site-packages/zzz_metacov.pth
 	@rm -f */.coverage */*/.coverage */*/*/.coverage */*/*/*/.coverage */*/*/*/*/.coverage */*/*/*/*/*/.coverage
 	@rm -f tests/covmain.zip tests/zipmods.zip tests/zip1.zip
diff --git a/igor.py b/igor.py
index c01cc7593..12e63f09b 100644
--- a/igor.py
+++ b/igor.py
@@ -200,6 +200,7 @@ def do_combine_html():
     show_contexts = bool(os.environ.get('COVERAGE_DYNCTX') or os.environ.get('COVERAGE_CONTEXT'))
     cov.html_report(show_contexts=show_contexts)
     cov.xml_report()
+    cov.json_report(pretty_print=True)
 
 
 def do_test_with_tracer(tracer, *runner_args):