diff --git a/CMakeLists.txt b/CMakeLists.txt
index c524f167..e656184d 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -163,6 +163,9 @@ endif()
 
 if(USE_OPENSSL_MD5)
     list(APPEND LXW_PRIVATE_COMPILE_DEFINITIONS USE_OPENSSL_MD5)
+    if(NOT MSVC)
+        set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -Wno-deprecated-declarations")
+    endif()
 endif()
 
 if(USE_MEM_FILE OR USE_FMEMOPEN)
diff --git a/src/Makefile b/src/Makefile
index 5caba2bc..a273fd32 100644
--- a/src/Makefile
+++ b/src/Makefile
@@ -49,7 +49,7 @@ ifdef USE_NO_MD5
 CFLAGS += -DUSE_NO_MD5
 else
 ifdef USE_OPENSSL_MD5
-CFLAGS += -DUSE_OPENSSL_MD5
+CFLAGS += -DUSE_OPENSSL_MD5 -Wno-deprecated-declarations
 LIBS   += -lcrypto
 else
 # Use md5 (the default).