diff --git a/configure.ac b/configure.ac
index 75f23f32c1..0384cd8c52 100644
--- a/configure.ac
+++ b/configure.ac
@@ -148,6 +148,9 @@ if test "$ac_cv_type_long_long_int" = yes; then
   AC_CHECK_SIZEOF(long long)
 fi
 
+# egrep is used in lib/Makefile.am
+AC_PROG_EGREP
+
 ### We need iconv for unicode support (Qt4 frontend requires it too)
 LYX_USE_INCLUDED_ICONV