diff --git a/src/config/config.js b/src/config/config.js
index 6f430f97..5a0a675d 100644
--- a/src/config/config.js
+++ b/src/config/config.js
@@ -30,6 +30,8 @@ export default {
   encryption_cipher: enums.symmetric.aes256,
   /** @property {Integer} compression Default compression algorithm {@link module:enums.compression} */
   compression: enums.compression.uncompressed,
+  /** @property {Integer} deflate_level Default zip/zlib compression level, between 1 and 9 */
+  deflate_level: 6,
 
   /**
    * Use Authenticated Encryption with Additional Data (AEAD) protection for symmetric encryption.
diff --git a/src/packet/compressed.js b/src/packet/compressed.js
index 258c605f..a726a103 100644
--- a/src/packet/compressed.js
+++ b/src/packet/compressed.js
@@ -31,6 +31,7 @@
  */
 
 import pako from 'pako';
+import config from '../config';
 import enums from '../enums.js';
 import util from '../util.js';
 import Bzip2 from '../compression/bzip2.build.js';
@@ -38,6 +39,12 @@ import Bzip2 from '../compression/bzip2.build.js';
 const nodeZlib = util.getNodeZlib();
 const Buffer = util.getNodeBuffer();
 
+function node_zlib(func, options = {}) {
+  return function (data) {
+    return func(data, options);
+  };
+}
+
 function pako_zlib(constructor, options = {}) {
   return function(data) {
       const obj = new constructor(options);
@@ -51,23 +58,23 @@ let decompress_fns;
 if (nodeZlib) { // Use Node native zlib for DEFLATE compression/decompression
   compress_fns = {
     // eslint-disable-next-line no-sync
-    zip: nodeZlib.deflateRawSync,
+    zip: node_zlib(nodeZlib.deflateRawSync, { level: config.deflate_level }),
     // eslint-disable-next-line no-sync
-    zlib: nodeZlib.deflateSync,
+    zlib: node_zlib(nodeZlib.deflateSync, { level: config.deflate_level }),
     bzip2: Bzip2.compressFile
   };
 
   decompress_fns = {
     // eslint-disable-next-line no-sync
-    zip: nodeZlib.inflateRawSync,
+    zip: node_zlib(nodeZlib.inflateRawSync),
     // eslint-disable-next-line no-sync
-    zlib: nodeZlib.inflateSync,
+    zlib: node_zlib(nodeZlib.inflateSync),
     bzip2: Bzip2.decompressFile
   };
 } else { // Use JS fallbacks
   compress_fns = {
-    zip: pako_zlib(pako.Deflate, { raw: true }),
-    zlib: pako_zlib(pako.Deflate),
+    zip: pako_zlib(pako.Deflate, { raw: true, level: config.deflate_level }),
+    zlib: pako_zlib(pako.Deflate, { level: config.deflate_level }),
     bzip2: Bzip2.compressFile
   };