diff --git a/src/transaction/sign.ts b/src/transaction/sign.ts
index cd80a27a..ae90fb8d 100644
--- a/src/transaction/sign.ts
+++ b/src/transaction/sign.ts
@@ -60,6 +60,72 @@ function signWithKeypair(
   }
 }
 
+/**
+ * Compares two objects and creates a diff.
+ *
+ * @param a An object to compare.
+ * @param b The other object to compare with.
+ *
+ * @returns An object containing the differences between the two objects.
+ */
+function objectDiff(a: object, b: object): object {
+  const diffs = {}
+
+  // Compare two items and push non-matches to object
+  const compare = function (i1: any, i2: any, k: string): void {
+    const type1 = Object.prototype.toString.call(i1)
+    const type2 = Object.prototype.toString.call(i2)
+    if (type2 === '[object Undefined]') {
+      diffs[k] = null // Indicate that the item has been removed
+      return
+    }
+    if (type1 !== type2) {
+      diffs[k] = i2 // Indicate that the item has changed types
+      return
+    }
+    if (type1 === '[object Object]') {
+      const objDiff = objectDiff(i1, i2)
+      if (Object.keys(objDiff).length > 0) {
+        diffs[k] = objDiff
+      }
+      return
+    }
+    if (type1 === '[object Array]') {
+      if (!isEqual(i1, i2)) {
+        diffs[k] = i2 // If arrays do not match, add second item to diffs
+      }
+      return
+    }
+    if (type1 === '[object Function]') {
+      if (i1.toString() !== i2.toString()) {
+        diffs[k] = i2 // If functions differ, add second one to diffs
+      }
+      return
+    }
+    if (i1 !== i2) {
+      diffs[k] = i2
+    }
+  }
+
+  // Check items in first object
+  for (const key in a) {
+    if (a.hasOwnProperty(key)) {
+      compare(a[key], b[key], key)
+    }
+  }
+
+  // Get items that are in the second object but not the first
+  for (const key in b) {
+    if (b.hasOwnProperty(key)) {
+      if (!a[key] && a[key] !== b[key]) {
+        diffs[key] = b[key]
+      }
+    }
+  }
+
+  return diffs
+}
+
 /**
  *  Decode a serialized transaction, remove the fields that are added during the signing process,
  *  and verify that it matches the transaction prior to signing.
@@ -93,11 +159,12 @@ function checkTxSerialization(serialized: string, tx: utils.TransactionJSON): vo
 
   if (!isEqual(decoded, tx)) {
     const error = new utils.common.errors.ValidationError(
-      'Serialized transaction does not match original txJSON'
+      'Serialized transaction does not match original txJSON. See `error.data`'
     )
     error.data = {
       decoded,
-      tx
+      tx,
+      diff: objectDiff(tx, decoded)
     }
     throw error
   }
diff --git a/test/api-test.js b/test/api-test.js
index 4d070c8e..b20f7a6b 100644
--- a/test/api-test.js
+++ b/test/api-test.js
@@ -2679,6 +2679,37 @@ describe('RippleAPI', function () {
     );
   });
 
+  it('sign - throws when encoded tx does not match decoded tx - prepared order', async function () {
+    const order = {
+      direction: 'sell',
+      quantity: {
+        currency: 'USD',
+        counterparty: 'rvYAfWj5gh67oV6fW32ZzP3Aw4Eubs59B',
+        value: '3.140000'
+      },
+      totalPrice: {
+        currency: 'XRP',
+        value: '31415'
+      }
+    };
+    const prepared = await this.api.prepareOrder('r9cZA1mLK5R5Am25ArfXFmqgNwjZgnfk59', order, {
+      sequence: 123
+    });
+    const secret = 'shsWGZcmZz6YsWWmcnpfr6fLTdtFV';
+    try {
+      this.api.sign(prepared.txJSON, secret);
+      return Promise.reject(new Error('api.sign should have thrown'));
+    } catch (error) {
+      assert.equal(error.name, 'ValidationError');
+      assert.equal(error.message, 'Serialized transaction does not match original txJSON. See `error.data`');
+      assert.deepEqual(error.data.diff, {
+        TakerGets: {
+          value: '3.14'
+        }
+      });
+    }
+  });
+
   it('sign - throws when encoded tx does not match decoded tx - AccountSet', function () {
     const secret = 'shsWGZcmZz6YsWWmcnpfr6fLTdtFV';
     const request = {