diff --git a/encode.js b/encode.js
index 3320033..63f5149 100644
--- a/encode.js
+++ b/encode.js
@@ -3,17 +3,22 @@ module.exports = encode
 var MSB = 0x80
   , REST = 0x7F
   , MSBALL = ~REST
+  , INT = Math.pow(2, 31)
 
 function encode(num, out, offset) {
   out = out || []
   offset = offset || 0
   var oldOffset = offset
 
+  while(num >= INT) {
+    out[offset++] = (num & 0xFF) | MSB
+    num /= 128
+  }
   while(num & MSBALL) {
-    out[offset++] = (num & 0xFF) | MSB 
+    out[offset++] = (num & 0xFF) | MSB
     num >>>= 7
   }
-  out[offset] = num
+  out[offset] = num | 0
   
   encode.bytesWritten = offset - oldOffset + 1
   
diff --git a/package.json b/package.json
index 235f29d..1f8542f 100644
--- a/package.json
+++ b/package.json
@@ -19,6 +19,6 @@
   "author": "Chris Dickinson <chris@neversaw.us>",
   "license": "MIT",
   "devDependencies": {
-    "tape": "~0.2.2"
+    "tape": "~2.12.3"
   }
-}
+}
\ No newline at end of file
diff --git a/test.js b/test.js
index 12f2e8f..0769851 100644
--- a/test.js
+++ b/test.js
@@ -71,6 +71,42 @@ test('encode multiple byte with zero first byte', function(assert) {
   assert.end()
 })
 
+test('big integers', function (assert) {
+
+  var bigs = []
+  for(var i = 32; i <= 53; i++) (function (i) {
+    bigs.push(Math.pow(2, i) - 1)
+    bigs.push(Math.pow(2, i))
+  })(i)
+
+  bigs.forEach(function (n) {
+    var data = encode(n)
+    console.error(n, '->', data)
+    assert.equal(decode(data), n)
+    assert.notEqual(decode(data), n - 1)
+  })
+  assert.end()
+})
+
+test('fuzz test - big', function(assert) {
+  var expect
+    , encoded
+
+  var MAX_INTD = Math.pow(2, 55)
+  var MAX_INT = Math.pow(2, 31)
+
+  for(var i = 0, len = 100; i < len; ++i) {
+    expect = randint(MAX_INTD - MAX_INT) + MAX_INT
+    encoded = encode(expect)
+    var data = decode(encoded)
+    assert.equal(expect, data, 'fuzz test: ' + expect.toString())
+    assert.equal(decode.bytesRead, encoded.length)
+  }
+
+  assert.end()
+})
+
+
 function randint(range) {
-  return ~~(Math.random() * range)  
+  return Math.floor(Math.random() * range)
 }