diff --git a/CMakeLists.txt b/CMakeLists.txt
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -1,13 +1,24 @@
 CMAKE_MINIMUM_REQUIRED(VERSION 2.6)
 
-IF(EXISTS ${CMAKE_SOURCE_DIR}/cmake/version.cmake)
-  INCLUDE(${CMAKE_SOURCE_DIR}/cmake/version.cmake)
-ELSE(EXISTS ${CMAKE_SOURCE_DIR}/cmake/version.cmake)
-  SET(PROJECT_NAME "LEMON")
-  SET(PROJECT_VERSION "hg-tip" CACHE STRING "LEMON version string.")
-ENDIF(EXISTS ${CMAKE_SOURCE_DIR}/cmake/version.cmake)
+SET(PROJECT_NAME "LEMON")
+PROJECT(${PROJECT_NAME})
 
-PROJECT(${PROJECT_NAME})
+IF(EXISTS ${PROJECT_SOURCE_DIR}/cmake/version.cmake)
+  INCLUDE(${PROJECT_SOURCE_DIR}/cmake/version.cmake)
+ELSEIF(DEFINED ENV{LEMON_VERSION})
+  SET(LEMON_VERSION $ENV{LEMON_VERSION} CACHE STRING "LEMON version string.")
+ELSE()
+  EXECUTE_PROCESS(
+    COMMAND hg id -i
+    WORKING_DIRECTORY ${PROJECT_SOURCE_DIR}
+    OUTPUT_VARIABLE HG_REVISION
+    ERROR_QUIET
+    OUTPUT_STRIP_TRAILING_WHITESPACE
+  )
+  SET(LEMON_VERSION ${HG_REVISION} CACHE STRING "LEMON version string.")
+ENDIF()
+
+SET(PROJECT_VERSION ${LEMON_VERSION})
 
 SET(CMAKE_MODULE_PATH ${PROJECT_SOURCE_DIR}/cmake)
 
diff --git a/cmake/version.cmake.in b/cmake/version.cmake.in
--- a/cmake/version.cmake.in
+++ b/cmake/version.cmake.in
@@ -1,2 +1,1 @@
-SET(PROJECT_NAME "@PACKAGE_NAME@")
-SET(PROJECT_VERSION "@PACKAGE_VERSION@" CACHE STRING "LEMON version string.")
+SET(LEMON_VERSION "@PACKAGE_VERSION@" CACHE STRING "LEMON version string.")
diff --git a/configure.ac b/configure.ac
--- a/configure.ac
+++ b/configure.ac
@@ -19,6 +19,8 @@
 AC_CONFIG_SRCDIR([lemon/list_graph.h])
 AC_CONFIG_HEADERS([config.h lemon/config.h])
 
+AC_DEFINE([LEMON_VERSION], [lemon_version()], [The version string])
+
 dnl Do compilation tests using the C++ compiler.
 AC_LANG([C++])
 
diff --git a/lemon/config.h.cmake b/lemon/config.h.cmake
--- a/lemon/config.h.cmake
+++ b/lemon/config.h.cmake
@@ -1,3 +1,4 @@
+#define LEMON_VERSION "@PROJECT_VERSION@"
 #cmakedefine LEMON_HAVE_LONG_LONG 1
 #cmakedefine LEMON_HAVE_LP 1
 #cmakedefine LEMON_HAVE_MIP 1
diff --git a/lemon/config.h.in b/lemon/config.h.in
--- a/lemon/config.h.in
+++ b/lemon/config.h.in
@@ -1,3 +1,6 @@
+/* The version string */
+#undef LEMON_VERSION
+
 /* Define to 1 if you have long long */
 #undef LEMON_HAVE_LONG_LONG