Abstract: A record of out-crossing in pigeonpea (Cajanus cajan (L.) Millsp.) from 32 locations indicated a large variation within and across 12 countries of Asia, Africa, and Americas. Pigeonpea breeders have exploited the natural hybrids within landraces for developing high yielding inbred cultivars in different countries. Similarly, natural hybrids selected from wild relatives of pigeonpea have been used to breed male sterility systems. During the last 40 years the importance of natural out-crossing in genetic enhancement of yield in pigeonpea has been well recognized, particularly in developing commercial hybrid technology; and it has allowed thousands of Indian farmers to harvest 30-40% more grains. This review provides an update on various aspects of natural out-crossing such as pollinating agents, extent of out-crossing, factors influencing out-crossing; besides this, the successful role of out-crossing in the genetic enhancement of yield in pigeonpea has also been discussed.