diff --git a/client/gridfs.cpp b/client/gridfs.cpp
index e5959a3..3a54109 100644
--- a/client/gridfs.cpp
+++ b/client/gridfs.cpp
@@ -50,7 +50,7 @@ namespace mongo {
     GridFS::GridFS( DBClientBase& client , const string& dbName , const string& prefix ) : _client( client ) , _dbName( dbName ) , _prefix( prefix ){
         _filesNS = dbName + "." + prefix + ".files";
         _chunksNS = dbName + "." + prefix + ".chunks";
-
+        _chunkSize = DEFAULT_CHUNK_SIZE;
 
         client.ensureIndex( _filesNS , BSON( "filename" << 1 ) );
         client.ensureIndex( _chunksNS , BSON( "files_id" << 1 << "n" << 1 ) );
@@ -60,6 +60,11 @@ namespace mongo {
 
     }
 
+    void GridFS::setChunkSize(unsigned int size) {
+        massert( 13295 , "invalid chunk size is specified", (size == 0));
+        _chunkSize = size;
+    }
+
     BSONObj GridFS::storeFile( const char* data , size_t length , const string& remoteName , const string& contentType){
         massert( 10279 , "large files not yet implemented", length <= 0xffffffff);
         char const * const end = data + length;
@@ -70,7 +75,7 @@ namespace mongo {
 
         int chunkNumber = 0;
         while (data < end){
-            int chunkLen = MIN(DEFAULT_CHUNK_SIZE, (unsigned)(end-data));
+            int chunkLen = MIN(_chunkSize, (unsigned)(end-data));
             Chunk c(idObj, chunkNumber, data, chunkLen);
             _client.insert( _chunksNS.c_str() , c._data );
 
@@ -99,15 +104,15 @@ namespace mongo {
         int chunkNumber = 0;
         gridfs_offset length = 0;
         while (!feof(fd)){
-            boost::scoped_array<char>buf (new char[DEFAULT_CHUNK_SIZE]);
+            boost::scoped_array<char>buf (new char[_chunkSize]);
             char* bufPos = buf.get();
             unsigned int chunkLen = 0; // how much in the chunk now
-            while(chunkLen != DEFAULT_CHUNK_SIZE && !feof(fd)){
-                int readLen = fread(bufPos, 1, DEFAULT_CHUNK_SIZE - chunkLen, fd);
+            while(chunkLen != _chunkSize && !feof(fd)){
+                int readLen = fread(bufPos, 1, _chunkSize - chunkLen, fd);
                 chunkLen += readLen;
                 bufPos += readLen;
 
-                assert(chunkLen <= DEFAULT_CHUNK_SIZE);
+                assert(chunkLen <= _chunkSize);
             }
 
             Chunk c(idObj, chunkNumber, buf.get(), chunkLen);
@@ -135,7 +140,7 @@ namespace mongo {
         file << "_id" << id
              << "filename" << name
              << "length" << (unsigned) length
-             << "chunkSize" << DEFAULT_CHUNK_SIZE
+             << "chunkSize" << _chunkSize
              << "uploadDate" << DATENOW
              << "md5" << res["md5"]
              ;
diff --git a/client/gridfs.h b/client/gridfs.h
index 3b8001b..89892c9 100644
--- a/client/gridfs.h
+++ b/client/gridfs.h
@@ -69,6 +69,11 @@ namespace mongo {
         ~GridFS();
 
         /**
+         * @param
+         */
+        void setChunkSize(unsigned int size);
+
+        /**
          * puts the file reference by fileName into the db
          * @param fileName local filename relative to process
          * @param remoteName optional filename to use for file stored in GridFS
@@ -123,6 +128,7 @@ namespace mongo {
         string _prefix;
         string _filesNS;
         string _chunksNS;
+        unsigned int _chunkSize;
 
         // insert fileobject. All chunks must be in DB.
         BSONObj insertFile(const string& name, const OID& id, unsigned length, const string& contentType);