My dad has agreed to cosign a lease with me but I am afraid my application will just be thrown out since I cannot provide a credit score or any proof of income. When do I need a cosigner?A cosigner for a rental property is someone who agrees to pay the rent if you cannot. Your rental application is your opportunity to stand out amongst other applicants, so pay attention to spelling and grammar. If you have a low credit score or have yet to establish a credit history, you may need to find someone to co-sign your application. When requested, applicants can enter other co-applicants, co-signers, and guarantors they'll be applying with on their rental application.