diff --git a/CMakeLists.txt b/CMakeLists.txt
index 90bddf2e..47ab5998 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -217,11 +217,13 @@ endif(EXAGO_ENABLE_GPU)
 if(EXAGO_ENABLE_PETSC)
   include(FindPkgConfig)
   # Include petsc package path in pkg_config_path
+  set(PKG_CONFIG_PATH_save $ENV{PKG_CONFIG_PATH})
   set(ENV{PKG_CONFIG_PATH}
       ${PETSC_DIR}/lib/pkgconfig:${PETSC_DIR}/${PETSC_ARCH}/lib/pkgconfig
   )
   pkg_check_modules(PETSC REQUIRED IMPORTED_TARGET PETSc)
   set(EXAGO_HAVE_PETSC 1)
+  set(ENV{PKG_CONFIG_PATH} ${PKG_CONFIG_PATH_save})
 endif()
 
 # Set install rpath to the locations where EXAGO and PETSc libraries reside.