A collection of 167 winged bean stocks (Psophocarpus tetragonolobus (L.) DC.) was evaluated at the Mayaguez Institute of Tropical agriculture in Puerto Rico. Dry seed yield per plant averaged 156 g and ranged from 43 to 328 g. These data were extrapolated to a mean protein yield of 479 kg/ha with a range of from 136 to 1062 kg/ha. Oil content varied from 14·3 to 19·1 per cent with a mean of 16·79 per cent. Protein content (C) and dry seed yield (Y) were inversely related (Ce=35·4-0·007Y), so selection for dry seed yield will be more effective than selection for protein content in increasing net protein yield. Dry seed yield was not correlated with either oil content or flowering time. Dry seed yield was related to the number of day· to final harvest but that relationship was lost when three stocks with very low yields were eliminated from the analysis. Plants produced an average of 311 mg of protein per day with a range of from 113 to 697 mg/day. Protein production per day and total dry seed yield per plant are apparently very strongly correlated.