diff --git a/lemon/CMakeLists.txt b/lemon/CMakeLists.txt
--- a/lemon/CMakeLists.txt
+++ b/lemon/CMakeLists.txt
@@ -28,6 +28,11 @@
   ENDIF(WIN32)
 ENDIF(HAVE_GLPK)
 
+IF(HAVE_CPLEX)
+  SET(LEMON_SOURCES ${LEMON_SOURCES} cplex.cc)
+  INCLUDE_DIRECTORIES(${CPLEX_INCLUDE_DIRS})
+ENDIF(HAVE_CPLEX)
+
 ADD_LIBRARY(lemon ${LEMON_SOURCES})
 
 INSTALL(