diff --git a/DQMServices/Components/test/run_fastHadd_tests.sh b/DQMServices/Components/test/run_fastHadd_tests.sh
index 53f0d1b469d7d..d29d5b937453e 100755
--- a/DQMServices/Components/test/run_fastHadd_tests.sh
+++ b/DQMServices/Components/test/run_fastHadd_tests.sh
@@ -22,7 +22,7 @@ set_up() {
 generate() {
     echo "Generating files"
 
-    python ${LOCAL_TEST_DIR}/test_fastHaddMerge.py -a produce -n $numFiles 2>&1 > /dev/null
+    python3 ${LOCAL_TEST_DIR}/test_fastHaddMerge.py -a produce -n $numFiles 2>&1 > /dev/null
 
     if [ $? -ne 0 ]; then
         exit $?
@@ -65,7 +65,7 @@ hadd_merge() {
 check_hadd() {
     echo "Checking ROOT result..."
 
-    python ${LOCAL_TEST_DIR}/test_fastHaddMerge.py -a check -n $numFiles -c $cumRootFile 2>&1 > /dev/null
+    python3 ${LOCAL_TEST_DIR}/test_fastHaddMerge.py -a check -n $numFiles -c $cumRootFile 2>&1 > /dev/null
 
     if [ $? -ne 0 ]; then
         exit $?
@@ -101,7 +101,7 @@ convertPB2ROOT() {
 check_fasthadd() {
     echo "Checking PB result... on ${cumPBFile_inROOT}"
 
-    python ${LOCAL_TEST_DIR}/test_fastHaddMerge.py -a check -n $numFiles -c $cumPBFile_inROOT 2>&1 > /dev/null
+    python3 ${LOCAL_TEST_DIR}/test_fastHaddMerge.py -a check -n $numFiles -c $cumPBFile_inROOT 2>&1 > /dev/null
 
     if [ $? -ne 0 ]; then
         exit $?
@@ -135,7 +135,7 @@ convert() {
 check_fasthadd_parallel() {
     echo "Checking PB result... on ${cumPBFileThreaded_inROOT}"
 
-    python ${LOCAL_TEST_DIR}/test_fastHaddMerge.py -a check -n $numFiles -c $cumPBFileThreaded_inROOT 2>&1 > /dev/null
+    python3 ${LOCAL_TEST_DIR}/test_fastHaddMerge.py -a check -n $numFiles -c $cumPBFileThreaded_inROOT 2>&1 > /dev/null
 
     if [ $? -ne 0 ]; then
         exit $?