Soy milk was produced from full fat flour by preparing a slurry in water at a water to flour ratio of 10 to 1. The slurry was heated to 50°C, and different enzymes were evaluated in order to optimize protein and solids yields in the milk. The reaction period was 1 hr and after inactivation of the enzymes by boiling for 15 min the mixtures were centrifuged at 1500 ×g and the protein and dry matter solubility indices (PSI and DSI) were calculated together with protein and dry matter yields in the obtained milk. The best results were obtained with a neutral proteinase, increasing the protein and solids yields from 33% and 42%, respectively, to 73% and 66%, respectively, at 0.5% dosage level compared to the control sample with no enzyme treatment.