diff --git a/moto/s3/models.py b/moto/s3/models.py
index d80eec417..2462d59be 100644
--- a/moto/s3/models.py
+++ b/moto/s3/models.py
@@ -1,5 +1,7 @@
 # from boto.s3.bucket import Bucket
 # from boto.s3.key import Key
+import os
+import base64
 import md5
 
 from moto.core import BaseBackend
@@ -21,10 +23,40 @@ class FakeKey(object):
         return len(self.value)
 
 
+class FakeMultipart(object):
+    def __init__(self, key_name):
+        self.key_name = key_name
+        self.parts = {}
+        self.id = base64.b64encode(os.urandom(43)).replace('=', '')
+
+    def complete(self):
+        total = bytearray()
+
+        for part_id, index in enumerate(sorted(self.parts.keys()), start=1):
+            # Make sure part ids are continuous
+            if part_id != index:
+                return
+
+            total.extend(self.parts[part_id])
+
+        if len(total) < 5242880:
+            return
+
+        return total
+
+    def set_part(self, part_id, value):
+        if part_id < 1:
+            return False
+
+        self.parts[part_id] = value
+        return True
+
+
 class FakeBucket(object):
     def __init__(self, name):
         self.name = name
         self.keys = {}
+        self.multiparts = {}
 
 
 class S3Backend(BaseBackend):
@@ -65,6 +97,27 @@ class S3Backend(BaseBackend):
         if bucket:
             return bucket.keys.get(key_name)
 
+    def initiate_multipart(self, bucket_name, key_name):
+        bucket = self.buckets[bucket_name]
+        new_multipart = FakeMultipart(key_name)
+        bucket.multiparts[new_multipart.id] = new_multipart
+
+        return new_multipart
+
+    def complete_multipart(self, bucket_name, multipart_id):
+        bucket = self.buckets[bucket_name]
+        multipart = bucket.multiparts[multipart_id]
+        value = multipart.complete()
+        if value is None:
+            return False
+
+        self.set_key(bucket_name, multipart.key_name, value)
+
+    def set_part(self, bucket_name, multipart_id, part_id, value):
+        bucket = self.buckets[bucket_name]
+        multipart = bucket.multiparts[multipart_id]
+        return multipart.set_part(part_id, value)
+
     def prefix_query(self, bucket, prefix):
         key_results = set()
         folder_results = set()
diff --git a/moto/s3/responses.py b/moto/s3/responses.py
index 80a0a9421..370c7cf5b 100644
--- a/moto/s3/responses.py
+++ b/moto/s3/responses.py
@@ -106,6 +106,20 @@ def key_response(uri_info, method, body, headers):
         removed_key = s3_backend.delete_key(bucket_name, key_name)
         template = Template(S3_DELETE_OBJECT_SUCCESS)
         return template.render(bucket=removed_key), dict(status=204)
+    elif method == 'POST':
+        if body == '' and uri_info.query == 'uploads':
+            multipart = s3_backend.initiate_multipart(bucket_name, key_name)
+            template = Template(S3_MULTIPART_RESPONSE)
+            response = template.render(
+                bucket_name=bucket_name,
+                key_name=key_name,
+                multipart_id=multipart.id,
+            )
+            print response
+            return response, dict()
+        else:
+            import pdb; pdb.set_trace()
+            raise NotImplementedError("POST is only allowed for multipart uploads")
     else:
         raise NotImplementedError("Method {} has not been impelemented in the S3 backend yet".format(method))
 
@@ -202,3 +216,16 @@ S3_OBJECT_COPY_RESPONSE = """<CopyObjectResponse xmlns="http://doc.s3.amazonaws.
     <LastModified>2008-02-18T13:54:10.183Z</LastModified>
   </CopyObjectResponse>
 </CopyObjectResponse>"""
+
+S3_MULTIPART_RESPONSE = """<?xml version="1.0" encoding="UTF-8"?>
+<InitiateMultipartUploadResult xmlns="http://s3.amazonaws.com/doc/2006-03-01/">
+  <Bucket>{{ bucket_name }}</Bucket>
+  <Key>{{ key_name }}</Key>
+  <UploadId>{{ upload_id }}</UploadId>
+</InitiateMultipartUploadResult>"""
+
+S3_MULTIPART_COMPLETE_RESPONSE = """
+"""
+
+S3_MULTIPART_ERROR_RESPONSE = """
+"""
diff --git a/tests/test_s3/test_s3.py b/tests/test_s3/test_s3.py
index 31e011bfc..1f713fabb 100644
--- a/tests/test_s3/test_s3.py
+++ b/tests/test_s3/test_s3.py
@@ -1,4 +1,5 @@
 import urllib2
+from io import BytesIO
 
 import boto
 from boto.exception import S3ResponseError
@@ -36,6 +37,26 @@ def test_my_model_save():
     conn.get_bucket('mybucket').get_key('steve').get_contents_as_string().should.equal('is awesome')
 
 
+@mock_s3
+def test_multipart_upload():
+    conn = boto.connect_s3('the_key', 'the_secret')
+    bucket = conn.create_bucket("foobar")
+
+    multipart = bucket.initiate_multipart_upload("the-key")
+    multipart.upload_part_from_file(BytesIO('hello'), 1)
+    multipart.upload_part_from_file(BytesIO('world'), 1)
+    # Multipart with total size under 5MB is refused
+    multipart.complete_upload().should.throw(S3ResponseError)
+
+    multipart = bucket.initiate_multipart_upload("the-key")
+    part1 = '0' * 5242880
+    multipart.upload_part_from_file(BytesIO('0' * 5242880), 1)
+    part2 = '1'
+    multipart.upload_part_from_file(BytesIO('1'), 1)
+    multipart.complete_upload()
+    bucket.get_key("the-key").get_contents_as_string().should.equal(part1 + part2)
+
+
 @mock_s3
 def test_missing_key():
     conn = boto.connect_s3('the_key', 'the_secret')