A crib safety sheet / blanket with a sheet portion having a front surface and a back surface, the back surface of the sheet portion being disposed adjacent to a mattress. A blanket is attached to the sheet portion, defining two blanket halves. Mating strips of hook and loop fastening material are attached to the two halves of the blanket, so that an infant may be placed on the blanket with the two halves of the blanket wrapped around the infant and fastened to retain the infant in a supine position. A plurality of straps extend across the bottom of the mattress, are attached to, or threaded through a spacer, and are removably secured to the side of the sheet portion with mating strips of hook and loop fastening material to retain the sheet on the mattress.