The objective of this study was to determine the effect of nitrogen on the production and abscission of reproductive organs and dry bean yield. This research was carried out in Iguala, Guerrero, Mexico where the climate is hot and subhumid. The Michoacan 12A3 bean variety, was sown on November 17, 1989, and December 17, 1990, with irrigation (autumn), and June 1, 1990 and June 29, 1991, without irrigation (summer). Population density was 13.3 plants/m-2. Treatments of zero and 80 kg N ha-1 were applied in each experiment. Results indicated that in both sowing seasons N increased leaf area, production and abscission of reproductive organs, number of pods reaching physiological maturity, and seed yield. As compared to the control, the higher abscission of reproductive organs in plants with N limited a higher seed yield under this treatment. Bean production in autumn was higher than in the summer.