Abstract Soils in the major bean ( Phaseolus vulgaris L.) producing regions of Latin America are frequently deficient in both P and N. With the fertilizer available to small farmers limited, the appropriate strategy for efficient fertilizer use could depend on the relative P requirements for plant and nodule development and N fixation in this species. In this field study the objective was to examine the growth, P distribution, and parameters of N 2 (C 2 H 2 ) fixation of bean cultivars at different levels of P fertilization. Seeds from 30 bean cultivars (replicates) were inoculated and lime pelleted, then sown into a Typic Dristandept soil low in available P. Phosphorus fertilization from 0 to 315 kg/ha as triple superphosphate was applied, then plant and nodule development, P distribution and N 2 (C 2 H 2 ) fixation measured 42 days after planting. Nodules were a strong sink for P, nodule weight increasing ninefold and P concentration in nodules by almost 50% over the range of P fertilization used. Other plant tissues benefited less. Levels of N 2 (C 2 H 2 ) fixation , specific nodule activity, and non structural carbohydrate in nodules were highly correlated with supply of P. Though P concentration in nodules reached 0.27%, there was no indication that the maximum fertilization rate used was adequate for full nodule development or nitrogen fixation. Further, none of the 30 cultivars tested showed reasonable N 2 (C 2 H 2 ) fixation at low rates of P fertilization. It may be concluded that identification of bean cultivars able to grow at low P, but still efficient in Na fixation, will be difficult.