diff --git a/easybuild/easyblocks/r/r.py b/easybuild/easyblocks/r/r.py
index 27d5d2ac32..1aaf408e28 100644
--- a/easybuild/easyblocks/r/r.py
+++ b/easybuild/easyblocks/r/r.py
@@ -70,8 +70,11 @@ def configure_step(self):
         for dep in ['Tcl', 'Tk']:
             root = get_software_root(dep)
             if root:
-                dep_config = os.path.join(root, 'lib', '%sConfig.sh' % dep.lower())
-                self.cfg.update('configopts', '--with-%s-config=%s' % (dep.lower(), dep_config))
+                for libdir in ['lib', 'lib64']:
+                    dep_config = os.path.join(root, libdir, '%sConfig.sh' % dep.lower())
+                    if os.path.exists(dep_config):
+                        self.cfg.update('configopts', '--with-%s-config=%s' % (dep.lower(), dep_config))
+                        break
 
         if "--with-x=" not in self.cfg['configopts'].lower():
             if get_software_root('X11'):