The objective of this study was to evaluate the effect of the soaking step and the domestic processing of the common bean, on the chemical composition, the levels of phytate, tannin, starch and flatulence factors by utilizing the follows treatments: raw bean (FC), freeze-dried cooked unsoaked bean (FCSM), freeze-dried cooked bean without the non-absorved soaking water (FCSAM), freeze-dried cooked bean with the non-absorved soaking water (FCCAM) and the soaking water (AM). The beans were soaking for a period for 16 hours in the proportion 3:1 (water:beans) at room temperature. The effect of the phytates and tannins on the net protein efficiency ratio (NPR) and protein digestibility using male Wistar rats were studied. A decrease in the phytate content of the beans (85%) with use of soaking was observed. In the case of the tannin content, only the cooking of the beans promoved high decomposition (84%). In the (FCSAM) treatment a decrease in the raffinose (25.0%), stachiose (24.8%), verbascose (41.7%) and starch (26.8%) contents was observed. Diets containing casein (control), casein plus the soluble solids obtain from the soaking water showed no significant difference (p>0.05) for the NPR, as well as for the different bean treatments, although these showing lower values. The treatment (FCSM) showed the higher digestibility (74.3+/-5.8%) of the bean treatments, the casein diets showing 94.6+/-0.9%. The reduction of the phytates, tannin, starch contents and flatulence factors in the common bean was most effective when the soaking water not absorved was descarted (FCSAM).513276283