diff --git a/lib/deflate.js b/lib/deflate.js
index 9cd0392..6768561 100644
--- a/lib/deflate.js
+++ b/lib/deflate.js
@@ -17,6 +17,7 @@ var Z_FINISH        = 4;
 
 var Z_OK            = 0;
 var Z_STREAM_END    = 1;
+var Z_SYNC_FLUSH    = 2;
 
 var Z_DEFAULT_COMPRESSION = -1;
 
@@ -46,7 +47,9 @@ var Z_DEFLATED  = 8;
  *
  * Compressed result, generated by default [[Deflate#onData]]
  * and [[Deflate#onEnd]] handlers. Filled after you push last chunk
- * (call [[Deflate#push]] with `Z_FINISH` / `true` param).
+ * (call [[Deflate#push]] with `Z_FINISH` / `true` param)  or if you
+ * push a chunk with explicit flush (call [[Deflate#push]] with
+ * `Z_SYNC_FLUSH` param).
  **/
 
 /**
@@ -170,8 +173,9 @@ var Deflate = function(options) {
  *
  * Sends input data to deflate pipe, generating [[Deflate#onData]] calls with
  * new compressed chunks. Returns `true` on success. The last data block must have
- * mode Z_FINISH (or `true`). That flush internal pending buffers and call
- * [[Deflate#onEnd]].
+ * mode Z_FINISH (or `true`). That will flush internal pending buffers and call
+ * [[Deflate#onEnd]]. For interim explicit flushes (without ending the stream) you
+ * can use mode Z_SYNC_FLUSH, keeping the compression context.
  *
  * On fail call [[Deflate#onEnd]] with error code and return false.
  *
@@ -224,7 +228,7 @@ Deflate.prototype.push = function(data, mode) {
       this.ended = true;
       return false;
     }
-    if (strm.avail_out === 0 || (strm.avail_in === 0 && _mode === Z_FINISH)) {
+    if (strm.avail_out === 0 || (strm.avail_in === 0 && (_mode === Z_FINISH || _mode === Z_SYNC_FLUSH))) {
       if (this.options.to === 'string') {
         this.onData(strings.buf2binstring(utils.shrinkBuf(strm.output, strm.next_out)));
       } else {
@@ -241,6 +245,13 @@ Deflate.prototype.push = function(data, mode) {
     return status === Z_OK;
   }
 
+  // callback interim results if Z_SYNC_FLUSH.
+  if (_mode === Z_SYNC_FLUSH) {
+    this.onEnd(Z_OK);
+    strm.avail_out = 0;
+    return true;
+  }
+
   return true;
 };
 
@@ -264,8 +275,9 @@ Deflate.prototype.onData = function(chunk) {
  * - status (Number): deflate status. 0 (Z_OK) on success,
  *   other if not.
  *
- * Called once after you tell deflate that input stream complete
- * or error happenned. By default - join collected chunks,
+ * Called once after you tell deflate that the input stream is
+ * complete (Z_FINISH) or should be flushed (Z_SYNC_FLUSH)
+ * or if an error happened. By default - join collected chunks,
  * free memory and fill `results` / `err` properties.
  **/
 Deflate.prototype.onEnd = function(status) {
diff --git a/lib/inflate.js b/lib/inflate.js
index 96915bc..f754336 100644
--- a/lib/inflate.js
+++ b/lib/inflate.js
@@ -30,7 +30,9 @@ var toString = Object.prototype.toString;
  *
  * Uncompressed result, generated by default [[Inflate#onData]]
  * and [[Inflate#onEnd]] handlers. Filled after you push last chunk
- * (call [[Inflate#push]] with `Z_FINISH` / `true` param).
+ * (call [[Inflate#push]] with `Z_FINISH` / `true` param) or if you
+ * push a chunk with explicit flush (call [[Inflate#push]] with
+ * `Z_SYNC_FLUSH` param).
  **/
 
 /**
@@ -150,8 +152,9 @@ var Inflate = function(options) {
  *
  * Sends input data to inflate pipe, generating [[Inflate#onData]] calls with
  * new output chunks. Returns `true` on success. The last data block must have
- * mode Z_FINISH (or `true`). That flush internal pending buffers and call
- * [[Inflate#onEnd]].
+ * mode Z_FINISH (or `true`). That will flush internal pending buffers and call
+ * [[Inflate#onEnd]]. For interim explicit flushes (without ending the stream) you
+ * can use mode Z_SYNC_FLUSH, keeping the decompression context.
  *
  * On fail call [[Inflate#onEnd]] with error code and return false.
  *
@@ -207,7 +210,7 @@ Inflate.prototype.push = function(data, mode) {
     }
 
     if (strm.next_out) {
-      if (strm.avail_out === 0 || status === c.Z_STREAM_END || (strm.avail_in === 0 && _mode === c.Z_FINISH)) {
+      if (strm.avail_out === 0 || status === c.Z_STREAM_END || (strm.avail_in === 0 && (_mode === c.Z_FINISH || _mode === c.Z_SYNC_FLUSH))) {
 
         if (this.options.to === 'string') {
 
@@ -233,6 +236,7 @@ Inflate.prototype.push = function(data, mode) {
   if (status === c.Z_STREAM_END) {
     _mode = c.Z_FINISH;
   }
+
   // Finalize on the last chunk.
   if (_mode === c.Z_FINISH) {
     status = zlib_inflate.inflateEnd(this.strm);
@@ -241,6 +245,13 @@ Inflate.prototype.push = function(data, mode) {
     return status === c.Z_OK;
   }
 
+  // callback interim results if Z_SYNC_FLUSH.
+  if (_mode === c.Z_SYNC_FLUSH) {
+    this.onEnd(c.Z_OK);
+    strm.avail_out = 0;
+    return true;
+  }
+
   return true;
 };
 
@@ -264,8 +275,9 @@ Inflate.prototype.onData = function(chunk) {
  * - status (Number): inflate status. 0 (Z_OK) on success,
  *   other if not.
  *
- * Called once after you tell inflate that input stream complete
- * or error happenned. By default - join collected chunks,
+ * Called either after you tell inflate that the input stream is
+ * complete (Z_FINISH) or should be flushed (Z_SYNC_FLUSH)
+ * or if an error happened. By default - join collected chunks,
  * free memory and fill `results` / `err` properties.
  **/
 Inflate.prototype.onEnd = function(status) {