Robert McLister·General·July 9, 2012Co-Borrower (Co-Signor) A co-borrower is an additional mortgage applicant that can help you qualify for a mortgage. A co-borrower is on title and responsible for the mortgage payments, along with all other applicants. A co-borrower is different than a guarantor. Like news like this?Join our CMT Updates list and get the latest news as it happens. Unsubscribe anytime. SUBSCRIBE! Thank you for subscribing. One more step: Please confirm your subscription via the email sent to you.