diff --git a/docs/index.md b/docs/index.md
index f4208824..f1e15f47 100644
--- a/docs/index.md
+++ b/docs/index.md
@@ -430,6 +430,7 @@ expirationTime | date-time string | *Optional* Time after which the offer is no
 fillOrKill | boolean | *Optional* Treat the offer as a [Fill or Kill order](http://en.wikipedia.org/wiki/Fill_or_kill). Only attempt to match existing offers in the ledger, and only do so if the entire quantity can be exchanged.
 immediateOrCancel | boolean | *Optional* Treat the offer as an [Immediate or Cancel order](http://en.wikipedia.org/wiki/Immediate_or_cancel). If enabled, the offer will never become a ledger node: it only attempts to match existing offers in the ledger.
 memos | [memos](#transaction-memos) | *Optional* Array of memos to attach to the transaction.
+orderToReplace | [sequence](#account-sequence-number) | *Optional* The [account sequence number](#account-sequence-number) of an order to cancel before the new order is created, effectively replacing the old order.
 passive | boolean | *Optional* If enabled, the offer will not consume offers that exactly match it, and instead becomes an Offer node in the ledger. It will still consume offers that cross it.
 
 ### Example
diff --git a/src/common/schemas/specifications/order.json b/src/common/schemas/specifications/order.json
index 84e5cb9b..5ee42b98 100644
--- a/src/common/schemas/specifications/order.json
+++ b/src/common/schemas/specifications/order.json
@@ -34,6 +34,10 @@
       "format": "date-time",
       "description": "Time after which the offer is no longer active, as an [ISO 8601 date-time](https://en.wikipedia.org/wiki/ISO_8601)."
     },
+    "orderToReplace": {
+      "$ref": "sequence",
+      "description": "The [account sequence number](#account-sequence-number) of an order to cancel before the new order is created, effectively replacing the old order."
+    },
     "memos": {"$ref": "memos"}
   },
   "required": ["direction", "quantity", "totalPrice"],
diff --git a/src/transaction/order.js b/src/transaction/order.js
index c7589044..d449dad8 100644
--- a/src/transaction/order.js
+++ b/src/transaction/order.js
@@ -1,5 +1,5 @@
 /* @flow */
-'use strict';
+'use strict'; // eslint-disable-line
 const _ = require('lodash');
 const utils = require('./utils');
 const offerFlags = utils.common.txFlags.OfferCreate;
@@ -35,6 +35,9 @@ function createOrderTransaction(account: string, order: Order): Object {
   if (order.expirationTime !== undefined) {
     txJSON.Expiration = iso8601ToRippleTime(order.expirationTime);
   }
+  if (order.orderToReplace !== undefined) {
+    txJSON.OfferSequence = order.orderToReplace;
+  }
   if (order.memos !== undefined) {
     txJSON.Memos = _.map(order.memos, utils.convertMemo);
   }
diff --git a/test/fixtures/requests/prepare-order-sell.json b/test/fixtures/requests/prepare-order-sell.json
index 6f1d587e..fca72e81 100644
--- a/test/fixtures/requests/prepare-order-sell.json
+++ b/test/fixtures/requests/prepare-order-sell.json
@@ -10,6 +10,7 @@
     "value": "2"
   },
   "immediateOrCancel": true,
+  "orderToReplace": 12345,
   "memos": [
     {
       "type": "test",
diff --git a/test/fixtures/responses/prepare-order-sell.json b/test/fixtures/responses/prepare-order-sell.json
index 43afec8a..75a51282 100644
--- a/test/fixtures/responses/prepare-order-sell.json
+++ b/test/fixtures/responses/prepare-order-sell.json
@@ -1,5 +1,5 @@
 {
-  "txJSON": "{\"TransactionType\":\"OfferCreate\",\"Account\":\"r9cZA1mLK5R5Am25ArfXFmqgNwjZgnfk59\",\"TakerGets\":{\"currency\":\"USD\",\"issuer\":\"rMH4UxPrbuMa1spCBR98hLLyNJp4d8p4tM\",\"value\":\"10.1\"},\"TakerPays\":\"2000000\",\"Flags\":2148139008,\"Memos\":[{\"Memo\":{\"MemoData\":\"7465787465642064617461\",\"MemoType\":\"74657374\",\"MemoFormat\":\"706C61696E2F74657874\"}}],\"LastLedgerSequence\":8820051,\"Fee\":\"12\",\"Sequence\":23}",
+  "txJSON": "{\"TransactionType\":\"OfferCreate\",\"Account\":\"r9cZA1mLK5R5Am25ArfXFmqgNwjZgnfk59\",\"TakerGets\":{\"currency\":\"USD\",\"issuer\":\"rMH4UxPrbuMa1spCBR98hLLyNJp4d8p4tM\",\"value\":\"10.1\"},\"TakerPays\":\"2000000\",\"Flags\":2148139008,\"Memos\":[{\"Memo\":{\"MemoData\":\"7465787465642064617461\",\"MemoType\":\"74657374\",\"MemoFormat\":\"706C61696E2F74657874\"}}],\"LastLedgerSequence\":8820051,\"Fee\":\"12\",\"Sequence\":23,\"OfferSequence\":12345}",
   "instructions": {
     "fee": "0.000012",
     "sequence": 23,