To evaluate the impact of single visit of Xylocopa olivacea on pod and seed yields of Phaseolus vulgaris Large White Seeds variety, its foraging and pollinating activities were studied in Sarh, during 2015 and 2016 rainy seasons. Treatments included unlimited flowers access by all visitors, bagged flowers, flowers limited visits by X. olivacea only and flowers bagged, opened and closed without insect or other organism visits. The foraging behavior of X. olivacea on flowers and its pollination efficiency were recorded. Xylocopa olivacea was the most frequent visitor and it intensely and exclusively collected nectar. The fruiting rate of unprotected flowers is significantly higher than that of protected flowers. Through its pollination efficiency, X. olivacea provoked a significant increase of the fruiting rate by 52.27%, the number of seeds/pod by 30.79% and the percentage of normal seeds by 84.03%. Conservation of X. olivacea nest close to P. vulgaris (Large White Seeds variety) fields is recommended to improve pod and seed production in the region.