ABSTRACT:  In 1985 a captive breeding program for Geoffroy’s side-necked turtle, Phrynops geoffroanus, and Orbigny’s slider, Trachemys dorbigni, was initiated at São Paulo Zoo.  The program has facilitated the study of turtle biology and behavior, and methods for large-scale breeding, necessary for future reintroduction programs, have been developed.  The methods are applicable to the breeding of related endangered species and may be of use to other Brazilian zoos.