Five experiments carried out over three years are described in which the effects of irrigation at various growth stages on the yield of peas from plants grown at different plant densities were determined. Results showed that, irrespective of the density at which the plants were grown, plants irrigated at the start of flowering and again as the pods were swelling produced significantly higher yields than unirrigated plants. Yield of peas per plant was consistently reduced as density increased but yield per unit area did not show a consistent relationship with plant density from year to year. The results indicated that, even when irrigation is available, plant densities of five to six plants per sq. ft. should not be exceeded.