Peruvian Diving-petrel (Pelecanoides garnotii) populations were surveyed at the species' main breeding areas and on islands where former colonies were known to exist. Nesting was found only on San Gallan and La Vieja islands on the central coast of Peru. For both islands, a minimum of 12,216 breeding pairs and a maximum of 13,270 pairs were estimated. San Gallän and La Vieja are within the Paracas National Reserve, but human activities on these islands could endanger the population because of unrestricted access to the colonies.