Abstract: The processing methods of soymilk were investigated with major focus on their effects on the nutritional values of soy yoghurt. Various chemicals such as: sodium hydroxide, sodium carbonate, sodium hydrogen carbonate and deionized water were used for treating different samples of soybeans. Soy yoghurt was prepared from the soymilk obtained from all the samples using a mixed starter culture containing Streptococcus thermophilus, Lactobacillus bulgaricus and Lactobacillus acidophilus. The yoghurt produced from the soymilk formed from soybeans sample treated with sodium carbonate solution recorded the highest mineral content (potassium-136.6 ppm, calcium-179.7 ppm, magnesium-652.2 ppm, sodium-495.0 ppm). Samples A and D with additional nutrient recorded pH value of 4.76 and 3.90 after 2 h of fermentation, respectively. This observation was due to the rapid increase in acid formation in the course of product formation. Sensory test evaluation revealed that soy yoghurt produced from soybeans sample treated with sodium hydroxide solution had the highest ratings in terms of taste, texture and overall acceptability.