diff --git a/Makefile.am b/Makefile.am
index ca045b9..7ec6322 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -58,6 +58,7 @@ fortrandir = $(datadir)/$(PACKAGE_NAME)/fortran/
 dist_fortran_DATA = $(qmckl_f)
 
 AM_CPPFLAGS = -I$(srcdir)/src -I$(srcdir)/include
+AM_FCFLAGS = -fno-underscoring
 
 lib_LTLIBRARIES = src/libqmckl.la
 src_libqmckl_la_SOURCES = $(qmckl_h) $(src_qmckl_f) $(C_FILES) $(F_FILES) $(H_PRIVATE_FUNC_FILES) $(H_PRIVATE_TYPE_FILES) $(header_tests)