diff --git a/modules/ECMGeneratePkgConfigFile.cmake b/modules/ECMGeneratePkgConfigFile.cmake
--- a/modules/ECMGeneratePkgConfigFile.cmake
+++ b/modules/ECMGeneratePkgConfigFile.cmake
@@ -156,9 +156,9 @@
     string(REPLACE ";" " " PKGCONFIG_TARGET_DEPS "${EGPF_DEPS}")
   endif ()
   if(IS_ABSOLUTE "${EGPF_INCLUDE_INSTALL_DIR}")
-      set(PKGCONFIG_TARGET_INCLUDES "-I${EGPF_INCLUDE_INSTALL_DIR}")
+      set(PKGCONFIG_TARGET_INCLUDES "${EGPF_INCLUDE_INSTALL_DIR}")
   else()
-      set(PKGCONFIG_TARGET_INCLUDES "-I${CMAKE_INSTALL_PREFIX}/${EGPF_INCLUDE_INSTALL_DIR}")
+      set(PKGCONFIG_TARGET_INCLUDES "${CMAKE_INSTALL_PREFIX}/${EGPF_INCLUDE_INSTALL_DIR}")
   endif()
   if(IS_ABSOLUTE "${EGPF_LIB_INSTALL_DIR}")
       set(PKGCONFIG_TARGET_LIBS "${EGPF_LIB_INSTALL_DIR}")
@@ -178,11 +178,16 @@
 
   file(WRITE ${PKGCONFIG_FILENAME}
 "
+prefix=${CMAKE_INSTALL_PREFIX}
+exec_prefix=${CMAKE_INSTALL_PREFIX}
+libdir=${CMAKE_INSTALL_PREFIX}/${EGPF_LIB_INSTALL_DIR}
+includedir=${PKGCONFIG_TARGET_INCLUDES}
+
 Name: ${PKGCONFIG_TARGET_LIBNAME}
 Description: ${PKGCONFIG_TARGET_DESCRIPTION}
 Version: ${PROJECT_VERSION}
 Libs: -L${CMAKE_INSTALL_PREFIX}/${EGPF_LIB_INSTALL_DIR} -l${PKGCONFIG_TARGET_LIBNAME}
-Cflags: ${PKGCONFIG_TARGET_INCLUDES} ${PKGCONFIG_TARGET_DEFINES}
+Cflags: -I${PKGCONFIG_TARGET_INCLUDES} ${PKGCONFIG_TARGET_DEFINES}
 Requires: ${PKGCONFIG_TARGET_DEPS}
 "
   )
diff --git a/tests/ECMGeneratePkgConfigFile/KF5CoreAddons.pc b/tests/ECMGeneratePkgConfigFile/KF5CoreAddons.pc
--- a/tests/ECMGeneratePkgConfigFile/KF5CoreAddons.pc
+++ b/tests/ECMGeneratePkgConfigFile/KF5CoreAddons.pc
@@ -1,3 +1,7 @@
+prefix=/usr
+exec_prefix=/usr
+libdir=/usr/lib
+includedir=/usr/KCoreAddons
 
 Name: KF5CoreAddons
 Description: KF5CoreAddons test
diff --git a/tests/ECMGeneratePkgConfigFile/KF5CoreAddons2.pc b/tests/ECMGeneratePkgConfigFile/KF5CoreAddons2.pc
--- a/tests/ECMGeneratePkgConfigFile/KF5CoreAddons2.pc
+++ b/tests/ECMGeneratePkgConfigFile/KF5CoreAddons2.pc
@@ -1,3 +1,7 @@
+prefix=/usr
+exec_prefix=/usr
+libdir=/usr/lib
+includedir=/usr/KCoreAddons
 
 Name: KF5CoreAddons2
 Description: Addons to QtCore
diff --git a/tests/ECMGeneratePkgConfigFile/KF5CoreAddons3.pc b/tests/ECMGeneratePkgConfigFile/KF5CoreAddons3.pc
--- a/tests/ECMGeneratePkgConfigFile/KF5CoreAddons3.pc
+++ b/tests/ECMGeneratePkgConfigFile/KF5CoreAddons3.pc
@@ -1,3 +1,7 @@
+prefix=/usr
+exec_prefix=/usr
+libdir=/usr/lib
+includedir=/usr/KCoreAddons
 
 Name: KF5CoreAddons3
 Description: KF5CoreAddons3 library.