Coffea arabica var. bourbon, one of the main economic varieties grown in São Paulo is being subjected to successive selfing since 1933, in order to investigate the influence of this procedure on yield and development of the plants. Data concerning one trial are here discussed in which progenies of two So Bourbon mother trees were analysed in comparison with progenies S1, S2, S3, and S4 derived from these mother trees and also F1 hybrids between plants of the So, S2 and S4 generations. It has been observed that successive selfing do not influence yield, height or vigor of the coffee trees, percentaga of peaberry and elephant beans and also the size of the normal flat beans. The variance values for total yield (1955 to 1958), height and vigor of the trees do not show any tendency to be increased or reduced as a result of successive selfings. A comparison of the variances of F1 hybrids with the variances of the progenies of the parents of these hybrids indicated that, in a general way, the F1 hybrid variances relative to the yield, plant height and vigor were higher but not statistically significant, except in one comparison. These data indicate that in the Bourbon coffee natural selfing must be frequent such as happens in the cera variety of Coffeea arabica. They also pointed out that the selected Bourbon plants can be maintained by artificial selfing of their flowers for th.3 establishment of the multiplication plots, without expecting reduction in the yield or vigor of the plants. Artificial hybridization, for the further improvement of the bourbon variety must then be based on outcrosses with different genotypes.