Abstract: In this study, the effect of cooking time on the nutritional quality of soya milk was determined with a view of obtaining the approximate time at which soya milk should be cooked to have its optimum benefit for man. Standard laboratory conditions, methods and instruments were used to obtain the results of the experiments. The soya milk samples were cooked for 15, 30 and 45 min, respectively and there were significant differences in the nutritional composition of soya milk cooked between these time intervals. Soya milk cooked for 15 min was characterized by a moisture content of about 93.45%; ash 4.17%; protein 3.72%; lipids 12.0%; carbohydrates 80.11% and energy value of 443.32 kcal/100 g. On the other hand, the soya milk prepared for 30 min contained moisture content level of 92.29%; lipids 6.48%; energy value of 409.08%, ash 5.83%, crude protein 4.23% and carbohydrates 83.46%. The sample of soya milk prepared for 45 min was characterized by ash content of 6.0%, crude protein 4.74% and lower moisture content 90.36%, lipids 6.17%, carbohydrates 83.09% and energy value of 406.00 kcal/100 g. The minerals investigated gave the following results under treated time of 15, 30 and 45 min, respectively; sodium: 27, 23 and 27 mg/100 mL, potassium: 41, 60 and 62 mg/100 mL, magnesium: 32.2, 31 and 35 ppm and calcium: 109.5, 81 and 90.0 ppm, respectively. It was evident that there were varying degrees of changes that occurred in each of the chemical composition of the soya milk with respect to the different periods of cooking.