diff --git a/Makefile.am b/Makefile.am
index e811f56..1ac2fb5 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -885,6 +885,8 @@
 
 RelaxNGPythonTests:
 	@(if [ -x $(PYTHON) ] ; then \
+	    PYTHONPATH=$(top_builddir)/python:$(top_builddir)/python/.libs ; \
+	    export PYTHONPATH; \
 	    echo "## Relax-NG Python based test suite 1" ; \
 	    $(CHECKER) $(PYTHON) $(srcdir)/check-relaxng-test-suite.py ; \
 	    echo "## Relax-NG Python based test suite 2" ; \
@@ -893,6 +895,8 @@
 
 SchemasPythonTests:
 	@(if [ -x $(PYTHON) ] ; then \
+	    PYTHONPATH=$(top_builddir)/python:$(top_builddir)/python/.libs; \
+	    export PYTHONPATH; \
 	    echo "## XML Schemas datatypes Python based test suite" ; \
 	    $(CHECKER) $(PYTHON) $(srcdir)/check-xsddata-test-suite.py ; \
 	  fi)