diff --git a/CMakeLists.txt b/CMakeLists.txt
index 3a09b9b5497764e6d9f2b8780679794c6f848d9f..0d9790971dcd0a7887687207b46a0217d563774c 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -342,6 +342,9 @@ if("${CMAKE_BUILD_TYPE}" STREQUAL "Coverage")
     add_custom_target(coverage
       ALL # in coverage mode we do coverage!
 
+      # zero all counters
+      COMMAND ${FASTCOV} -q -z
+
       # Run tests
       COMMAND ${CMAKE_CTEST_COMMAND}