A non-negotiable check is a paper check or deposit slip that looks like a check but that cannot be exchanged for cash. It usually has the words "non-negotiable," "this is not a check" or "void" printed across the front to signal that it has no monetary value.
Non-negotiable checks are often used when setting up direct deposit in the workplace. Generally, employers require a check or deposit slip for the account into which payment is deposited. However, in order to prevent the theft of these blank checks and reduce the risk of check fraud, checks are rendered non-negotiable before being turned over to the employer.