the objective of this study was to evaluate the yam yield, cultivar da costa, fertilized with bovine manure doses and biofertilizer. the experimental design was randomized blocks, in subdivided plots 6 x 2 + 1 with three repetitions. in plots six doses of cattle manure (0; 6; 12; 18; 24 and 30 t ha-1) were tested, factorially combined with the presence and absence of biofertilizer and in subplots, two forms of application of biofertilizer in the soil and by spray on the leaf and an additional treatment with conventional fertilization (animal manure and npk). the doses of 30 t ha-1 of bovine manure and the biofertilizer which was applied in the soil and leaf produced tubers with ideal average weight for the commercialization. the bovine manure in doses of 19.2 t ha-1 and in the absence of biofertilizer provided maximum productivity of 20.3 t ha-1 of commercial tubers. subplots in which the biofertilizer was applied to the soil and leaf, the dose of 30 t ha-1 of cattle manure was responsible, respectively, for maximum yields of 22.8 and 24 t ha-1 of commercial tubers. the organic and conventional fertilizations did not cause any significant change in the mean tuber weight, but the conventional fertilization increased the productivity of commercial tuber.