diff --git a/packages/amazon-cognito-identity-js/index.d.ts b/packages/amazon-cognito-identity-js/index.d.ts
index 7f4d0451a33..e5d6e99d12f 100644
--- a/packages/amazon-cognito-identity-js/index.d.ts
+++ b/packages/amazon-cognito-identity-js/index.d.ts
@@ -24,11 +24,20 @@ declare module 'amazon-cognito-identity-js' {
 			userAttributes: any,
 			requiredAttributes: any
 		) => void;
-		mfaRequired?: (challengeName: any, challengeParameters: any) => void;
-		totpRequired?: (challengeName: any, challengeParameters: any) => void;
+		mfaRequired?: (
+			challengeName: ChallengeName,
+			challengeParameters: any
+		) => void;
+		totpRequired?: (
+			challengeName: ChallengeName,
+			challengeParameters: any
+		) => void;
 		customChallenge?: (challengeParameters: any) => void;
-		mfaSetup?: (challengeName: any, challengeParameters: any) => void;
-		selectMFAType?: (challengeName: any, challengeParameters: any) => void;
+		mfaSetup?: (challengeName: ChallengeName, challengeParameters: any) => void;
+		selectMFAType?: (
+			challengeName: ChallengeName,
+			challengeParameters: any
+		) => void;
 	}
 
 	export interface IMfaSettings {
@@ -67,9 +76,19 @@ declare module 'amazon-cognito-identity-js' {
 		clientMetadata: Record<string, string>;
 	}
 
+	export type ChallengeName =
+		| 'CUSTOM_CHALLENGE'
+		| 'MFA_SETUP'
+		| 'NEW_PASSWORD_REQUIRED'
+		| 'SELECT_MFA_TYPE'
+		| 'SMS_MFA'
+		| 'SOFTWARE_TOKEN_MFA';
+
 	export class CognitoUser {
 		constructor(data: ICognitoUserData);
 
+		challengeName?: ChallengeName;
+
 		public setSignInUserSession(signInUserSession: CognitoUserSession): void;
 		public getSignInUserSession(): CognitoUserSession | null;
 		public getUsername(): string;
@@ -246,8 +265,14 @@ declare module 'amazon-cognito-identity-js' {
 			callbacks: {
 				onSuccess: (session: CognitoUserSession) => void;
 				onFailure: (err: any) => void;
-				mfaRequired?: (challengeName: any, challengeParameters: any) => void;
-				totpRequired?: (challengeName: any, challengeParameters: any) => void;
+				mfaRequired?: (
+					challengeName: ChallengeName,
+					challengeParameters: any
+				) => void;
+				totpRequired?: (
+					challengeName: ChallengeName,
+					challengeParameters: any
+				) => void;
 			}
 		): void;
 	}
diff --git a/packages/auth/__tests__/auth-unit-test.ts b/packages/auth/__tests__/auth-unit-test.ts
index e4093155b2d..a877b935538 100644
--- a/packages/auth/__tests__/auth-unit-test.ts
+++ b/packages/auth/__tests__/auth-unit-test.ts
@@ -1011,7 +1011,7 @@ describe('auth unit test', () => {
 			const spyon = jest
 				.spyOn(CognitoUser.prototype, 'authenticateUser')
 				.mockImplementationOnce((authenticationDetails, callback) => {
-					callback.mfaRequired('challengeName', 'challengeParam');
+					callback.mfaRequired('SELECT_MFA_TYPE', 'challengeParam');
 				});
 			const auth = new Auth(authOptions);
 			const user = new CognitoUser({
@@ -1019,7 +1019,7 @@ describe('auth unit test', () => {
 				Pool: userPool,
 			});
 			const userAfterSignedIn = Object.assign({}, user, {
-				challengeName: 'challengeName',
+				challengeName: 'SELECT_MFA_TYPE',
 				challengeParam: 'challengeParam',
 			});
 
@@ -1035,7 +1035,7 @@ describe('auth unit test', () => {
 			const spyon = jest
 				.spyOn(CognitoUser.prototype, 'authenticateUser')
 				.mockImplementationOnce((authenticationDetails, callback) => {
-					callback.mfaSetup('challengeName', 'challengeParam');
+					callback.mfaSetup('MFA_SETUP', 'challengeParam');
 				});
 			const auth = new Auth(authOptions);
 			const user = new CognitoUser({
@@ -1043,7 +1043,7 @@ describe('auth unit test', () => {
 				Pool: userPool,
 			});
 			const userAfterSignedIn = Object.assign({}, user, {
-				challengeName: 'challengeName',
+				challengeName: 'MFA_SETUP',
 				challengeParam: 'challengeParam',
 			});
 
@@ -1059,7 +1059,7 @@ describe('auth unit test', () => {
 			const spyon = jest
 				.spyOn(CognitoUser.prototype, 'authenticateUser')
 				.mockImplementationOnce((authenticationDetails, callback) => {
-					callback.totpRequired('challengeName', 'challengeParam');
+					callback.totpRequired('SOFTWARE_TOKEN_MFA', 'challengeParam');
 				});
 			const auth = new Auth(authOptions);
 			const user = new CognitoUser({
@@ -1067,7 +1067,7 @@ describe('auth unit test', () => {
 				Pool: userPool,
 			});
 			const userAfterSignedIn = Object.assign({}, user, {
-				challengeName: 'challengeName',
+				challengeName: 'SOFTWARE_TOKEN_MFA',
 				challengeParam: 'challengeParam',
 			});
 
@@ -1083,7 +1083,7 @@ describe('auth unit test', () => {
 			const spyon = jest
 				.spyOn(CognitoUser.prototype, 'authenticateUser')
 				.mockImplementationOnce((authenticationDetails, callback) => {
-					callback.selectMFAType('challengeName', 'challengeParam');
+					callback.selectMFAType('SELECT_MFA_TYPE', 'challengeParam');
 				});
 			const auth = new Auth(authOptions);
 			const user = new CognitoUser({
@@ -1091,7 +1091,7 @@ describe('auth unit test', () => {
 				Pool: userPool,
 			});
 			const userAfterSignedIn = Object.assign({}, user, {
-				challengeName: 'challengeName',
+				challengeName: 'SELECT_MFA_TYPE',
 				challengeParam: 'challengeParam',
 			});
 
@@ -1403,7 +1403,7 @@ describe('auth unit test', () => {
 			const spyon = jest
 				.spyOn(CognitoUser.prototype, 'completeNewPasswordChallenge')
 				.mockImplementationOnce((password, requiredAttributes, callback) => {
-					callback.mfaRequired('challengeName', 'challengeParam');
+					callback.mfaRequired('SMS_MFA', 'challengeParam');
 				});
 
 			const auth = new Auth(authOptions);
@@ -1422,7 +1422,7 @@ describe('auth unit test', () => {
 			const spyon = jest
 				.spyOn(CognitoUser.prototype, 'completeNewPasswordChallenge')
 				.mockImplementationOnce((password, requiredAttributes, callback) => {
-					callback.mfaSetup('challengeName', 'challengeParam');
+					callback.mfaSetup('MFA_SETUP', 'challengeParam');
 				});
 
 			const auth = new Auth(authOptions);