diff --git a/src/fdcache_entity.cpp b/src/fdcache_entity.cpp
index a760cc0..685d1fb 100644
--- a/src/fdcache_entity.cpp
+++ b/src/fdcache_entity.cpp
@@ -2349,7 +2349,7 @@ ssize_t FdEntity::WriteStreamUpload(PseudoFdInfo* pseudo_obj, const char* bytes,
     //
     headers_t tmporgmeta  = orgmeta;
     bool      isuploading = pseudo_obj->IsUploading();
-    int       result;
+    ssize_t   result;
     if(0 != (result = pseudo_obj->UploadBoundaryLastUntreatedArea(path.c_str(), tmporgmeta, this))){
         S3FS_PRN_ERR("Failed to upload the last untreated parts(area) : result=%d", result);
         return result;
diff --git a/src/fdcache_fdinfo.cpp b/src/fdcache_fdinfo.cpp
index b796d7b..9d1838c 100644
--- a/src/fdcache_fdinfo.cpp
+++ b/src/fdcache_fdinfo.cpp
@@ -740,7 +740,7 @@ bool PseudoFdInfo::ExtractUploadPartsFromUntreatedArea(off_t& untreated_start, o
     // Add upload area to the list
     //
     while(max_mp_size <= aligned_size){
-        int part_num = (aligned_start / max_mp_size) + 1;
+        int part_num = static_cast<int>((aligned_start / max_mp_size) + 1);
         to_upload_list.push_back(mp_part(aligned_start, max_mp_size, part_num));
 
         aligned_start += max_mp_size;
@@ -888,7 +888,7 @@ bool PseudoFdInfo::ExtractUploadPartsFromAllArea(UntreatedParts& untreated_list,
         //
         // Create upload/download/cancel/copy list for this current area
         //
-        int part_num = (cur_start / max_mp_size) + 1;
+        int part_num = static_cast<int>((cur_start / max_mp_size) + 1);
         if(cur_untreated_list.empty()){
             //
             // No untreated area was detected in this current area
diff --git a/src/openssl_auth.cpp b/src/openssl_auth.cpp
index 9da395a..dcfe941 100644
--- a/src/openssl_auth.cpp
+++ b/src/openssl_auth.cpp
@@ -265,7 +265,7 @@ unsigned char* s3fs_md5_fd(int fd, off_t start, off_t size)
 {
     EVP_MD_CTX*    mdctx;
     unsigned char* md5_digest;
-    unsigned int   md5_digest_len = get_md5_digest_length();
+    unsigned int   md5_digest_len = static_cast<unsigned int>(get_md5_digest_length());
     off_t          bytes;
 
     if(-1 == size){
diff --git a/src/threadpoolman.cpp b/src/threadpoolman.cpp
index 1c8a65a..d5dc70e 100644
--- a/src/threadpoolman.cpp
+++ b/src/threadpoolman.cpp
@@ -198,7 +198,7 @@ bool ThreadPoolMan::StopThreads()
 
     // all threads to exit
     SetExitFlag(true);
-    for(uint waitcnt = thread_list.size(); 0 < waitcnt; --waitcnt){
+    for(size_t waitcnt = thread_list.size(); 0 < waitcnt; --waitcnt){
         thpoolman_sem.post();
     }