diff --git a/packages/amazon-cognito-identity-js/index.d.ts b/packages/amazon-cognito-identity-js/index.d.ts
index 7f4d0451a33..ca4480d1a32 100644
--- a/packages/amazon-cognito-identity-js/index.d.ts
+++ b/packages/amazon-cognito-identity-js/index.d.ts
@@ -63,6 +63,14 @@ declare module 'amazon-cognito-identity-js' {
 		Storage?: ICognitoStorage;
 	}
 
+	export type ChallengeName =
+		| 'CUSTOM_CHALLENGE'
+		| 'MFA_SETUP'
+		| 'NEW_PASSWORD_REQUIRED'
+		| 'SELECT_MFA_TYPE'
+		| 'SMS_MFA'
+		| 'SOFTWARE_TOKEN_MFA';
+
 	export interface GetSessionOptions {
 		clientMetadata: Record<string, string>;
 	}
@@ -70,7 +78,11 @@ declare module 'amazon-cognito-identity-js' {
 	export class CognitoUser {
 		constructor(data: ICognitoUserData);
 
-		public setSignInUserSession(signInUserSession: CognitoUserSession): void;
+		challengeName?: ChallengeName;
+
+		public setSignInUserSession(
+			signInUserSession: CognitoUserSession
+		): void;
 		public getSignInUserSession(): CognitoUserSession | null;
 		public getUsername(): string;