--- a/ykcs11/CMakeLists.txt
+++ b/ykcs11/CMakeLists.txt
@@ -30,7 +30,7 @@
 link_directories(${PCSC_LIBRARY_DIRS})
 add_definitions(-DCRYPTOKI_EXPORTS)
 if(NOT WIN32)
-    set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -fvisibility=hidden")
+    set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -fvisibility=hidden -pthread")
 endif(NOT WIN32)
 
 set(
@@ -63,7 +63,7 @@
 # static library
 if(BUILD_STATIC_LIB)
     add_library(ykcs11 STATIC ${SOURCE})
-    target_link_libraries(ykcs11 ${LIBCRYPTO_LDFLAGS} ykpiv_static)
+    target_link_libraries(ykcs11 ${LIBCRYPTO_LDFLAGS} -pthread ykpiv_static)
     set_target_properties (ykcs11 PROPERTIES COMPILE_FLAGS "-DSTATIC ")
     if(WIN32)
         set_target_properties(ykcs11 PROPERTIES OUTPUT_NAME ykcs11_static)
@@ -73,7 +73,7 @@
 
 # dynamic library
 add_library(ykcs11_shared SHARED ${SOURCE})
-target_link_libraries(ykcs11_shared ${LIBCRYPTO_LDFLAGS} ykpiv_shared)
+target_link_libraries(ykcs11_shared ${LIBCRYPTO_LDFLAGS} -pthread ykpiv_shared)
 set_target_properties(ykcs11_shared PROPERTIES SOVERSION ${SO_VERSION} VERSION ${VERSION})
 set_target_properties(ykcs11_shared PROPERTIES INSTALL_RPATH "${YKPIV_INSTALL_LIB_DIR}")
 if(WIN32)