diff --git a/bc.spec b/bc.spec
index 19c86fa..7758f27 100644
--- a/bc.spec
+++ b/bc.spec
@@ -1,7 +1,7 @@
 Summary: GNU's bc (a numeric processing language) and dc (a calculator).
 Name: bc
 Version: 1.06
-Release: 19.2.1
+Release: 20
 License: GPL
 URL: http://www.gnu.org/software/bc/
 Group: Applications/Engineering
@@ -11,7 +11,7 @@ Patch2: bc-1.06-s390.patch
 Patch3: bc-1.06-info_exp_bessel.patch
 Prereq: /sbin/install-info grep
 Buildroot: %{_tmppath}/%{name}-%{version}-root
-BuildRequires: readline-devel
+BuildRequires: readline-devel, flex
 
 %description
 The bc package includes bc and dc. Bc is an arbitrary precision
@@ -69,6 +69,9 @@ fi
 %{_infodir}/*
 
 %changelog
+* Tue Jun  6 2006 Thomas Woerner <twoerner@redhat.com> 1.06-20
+- added missing flex build require
+
 * Fri Feb 10 2006 Jesse Keating <jkeating@redhat.com> - 1.06-19.2.1
 - bump again for double-long bug on ppc(64)