Variations in self-fertility, expressed as percentages of drupelets set, were observed among 69 red raspberry cultivars or selections. The incidence of reduced self-fertility was particularly prevalent among some of the older cultivars but was also observed in several selections. In a particular cultivar or selection reduction of self-fertility usually followed both self- and open-pollination. Reductions from self-pollination seemed mostly to involve self-incompatibility although at least one was due to reduced pollen-fertility. Reductions from open-pollination probably involved reduced numbers of functional embryo sacs.