diff --git a/src/osgPlugins/curl/CMakeLists.txt b/src/osgPlugins/curl/CMakeLists.txt
index 83b61e9f9..f942fbb58 100644
--- a/src/osgPlugins/curl/CMakeLists.txt
+++ b/src/osgPlugins/curl/CMakeLists.txt
@@ -13,7 +13,7 @@ ENDIF(WIN32)
 
 IF(ZLIB_FOUND)
     ADD_DEFINITIONS(-DUSE_ZLIB)
-    INCLUDE_DIRECTORIES( ${CURL_INCLUDE_DIRS} ${ZLIB_INCLUDE_DIRS})
+    INCLUDE_DIRECTORIES( ${CURL_INCLUDE_DIRS} ${ZLIB_INCLUDE_DIR})
 ELSE(ZLIB_FOUND)
     INCLUDE_DIRECTORIES( ${CURL_INCLUDE_DIRS} )
 ENDIF(ZLIB_FOUND)
diff --git a/src/osgPlugins/gz/CMakeLists.txt b/src/osgPlugins/gz/CMakeLists.txt
index 6e14d6d3b..975e6fd07 100644
--- a/src/osgPlugins/gz/CMakeLists.txt
+++ b/src/osgPlugins/gz/CMakeLists.txt
@@ -1,5 +1,5 @@
 #this file is automatically generated 
-INCLUDE_DIRECTORIES( ${ZLIB_INCLUDE_DIRS} )
+INCLUDE_DIRECTORIES( ${ZLIB_INCLUDE_DIR} )
 
 SET(TARGET_SRC 
     ReaderWriterGZ.cpp
diff --git a/src/osgPlugins/ive/CMakeLists.txt b/src/osgPlugins/ive/CMakeLists.txt
index 5984b67f9..871dc2f66 100644
--- a/src/osgPlugins/ive/CMakeLists.txt
+++ b/src/osgPlugins/ive/CMakeLists.txt
@@ -1,6 +1,6 @@
 IF(ZLIB_FOUND)
     ADD_DEFINITIONS(-DUSE_ZLIB)
-    INCLUDE_DIRECTORIES( ${ZLIB_INCLUDE_DIRS})
+    INCLUDE_DIRECTORIES( ${ZLIB_INCLUDE_DIR})
 ENDIF(ZLIB_FOUND)