Self incompatibility has been shown to occur in all diploid species of the genus Coffea.The presence of alleles of self incompatibility in the diploid coffee populations demands breeding methods other than those used for Coffea arabica.The cross compatibility among plants of C. canephora'Guarini', and between individual plants of Guarini, 'Bangelan', 'Uganda' and 'Chalotti' of C. congensis, C. conuga, C. congensisx Ugandaand C. Ugandax congensis, with a mixture of pollen of Guarini, Robusta, Laurentii, Bangelan and Uganda was studied. Low fruit set was observed in the crosses within the cultivar Guarini indicating the presence of common alleles of incompatibility. Crosses made with pollen mixture gave better setting specially between Guarini and Robusta, Laurentii or Uganda x Congensis.High fruit set was observed in crosses involving cultivars of C. congensisand pollen mixture of cultivar Chalotti of the same species. The material obtained will be used for the establishment of selection plots. By crossing different cultivars or even by crossing C. canephoraand C. congensis it is possible to increase the restricted gene pool available for selection for each cultivar.