The breeding activities of rock pigeons (Columba guinea) on the campus of the University of the Orange Free State at Bloemfontein were investigated. In contrast to the marked seasonal variation in the mass of the ovary and diameter of macroscopic follicles experienced by females, the gonadal cycle of males appears to be relatively constant. Histological investigation of the testes confirms that adult individuals, in contrast to juveniles, are potentially capable of breeding activity throughout the year. Based on the occurrence of nests, eggs and nestlings, breeding activities of rock pigeons take place throughout the year. Nests, of which the selection of nesting material is influenced more by availability than type of item, were found only on the roofs and other structures of buildings. After hatching of a typical clutch size of two eggs, the daily increase in the mass of nestlings takes place in a linear fashion.