Described herein are tissue repair implants comprising at least a first layer of peritoneal membrane. The first layer of peritoneal membrane can be located adjacent to a second layer of peritoneal membrane and can be in direct contact with the second layer of peritoneal membrane. Additional layers (e.g., a third or fourth layer) can be included. Where more than one layer is present, the layers can be affixed to one another. For example, a first layer of peritoneal membrane can be attached to the second layer of peritoneal membrane by an adhesive bond, suture, or staple. One or more of the peritoneal membranes can be non-crosslinked, partially crosslinked, or substantially fully crosslinked. Any of the layers of peritoneal membrane may be attached to a wall (e.g., an interior or exterior wall) of an abdominal tissue by an adhesive, suture, and/or staples.