diff --git a/packages/hdnode/src.ts/index.ts b/packages/hdnode/src.ts/index.ts
index 848f471af9..4dadf220aa 100644
--- a/packages/hdnode/src.ts/index.ts
+++ b/packages/hdnode/src.ts/index.ts
@@ -212,8 +212,8 @@ export class HDNode implements ExternallyOwnedAccount {
     }
 
     static fromMnemonic(mnemonic: string, password?: string, wordlist?: Wordlist): HDNode {
-        // Check that the checksum s valid (will throw an error)
-        mnemonicToEntropy(mnemonic, wordlist);
+        // Normalize the case and spacing in the mnemonic (throws if the mnemonic is invalid)
+        mnemonic = entropyToMnemonic(mnemonicToEntropy(mnemonic, wordlist), wordlist);
 
         return HDNode._fromSeed(mnemonicToSeed(mnemonic, password), mnemonic);
     }
diff --git a/packages/tests/src.ts/test-hdnode.ts b/packages/tests/src.ts/test-hdnode.ts
index ad63158ac0..01d4eb29b1 100644
--- a/packages/tests/src.ts/test-hdnode.ts
+++ b/packages/tests/src.ts/test-hdnode.ts
@@ -3,7 +3,33 @@
 import assert from "assert";
 
 import { ethers } from "ethers";
-import { loadTests, TestCase } from "@ethersproject/testcases";
+import { loadTests, randomNumber, TestCase } from "@ethersproject/testcases";
+
+function randomCase(seed: string, text: string): string {
+    return text.split("").map(function(c, index) {
+       if (randomNumber(seed + "-" + index, 0, 2)) {
+           return c.toUpperCase();
+       }
+       return c
+    }).join("");
+}
+
+describe('Test HD Node Derivation is Case Agnostic', function() {
+    let tests: Array<TestCase.HDWallet> = loadTests('hdnode');
+    tests.forEach((test) => {
+        it("Normalizes case - " + test.name, function() {
+            this.timeout(10000);
+            let wordlist = (<{ [ locale: string ]: ethers.Wordlist }>(ethers.wordlists))[test.locale];
+
+            let rootNode = ethers.utils.HDNode.fromMnemonic(test.mnemonic, test.password || null, wordlist);
+
+            let altMnemonic = randomCase(test.name, test.mnemonic);
+            let altNode = ethers.utils.HDNode.fromMnemonic(altMnemonic, test.password || null, wordlist);
+
+            assert.equal(altNode.privateKey, rootNode.privateKey, altMnemonic);
+        });
+    });
+});
 
 describe('Test HD Node Derivation from Seed', function() {