The aim of this study was to assess the influence of different soaking and cooking methods on contents of selected nutrients in legume seeds. The experimental material were dried kidney-bean seeds and soya bean seeds originating from the collection of Krakow’s Plants and Seeds Horticulture POLAN LTD. Technological treatment of seeds was performed in two stages: (1) cold and hot soaking, (2) cooking with three different devices: electric and induction stoves and microwave apparatus. The experimental material was determined for contents of: dry matter, protein, fat, ash, carbohydrates and selected mineral compounds (Ca, Mg, Na, K). The soaking and cooking of the seeds were observed to affect an increase in contents of protein, fat, ash, calcium and sodium in dry matter as well as a decrease in contents of digestible carbohydrates, potassium and magnesium. A more favorable method of soaking kidney bean seeds turned out to be hot soaking, which caused smaller losses of nutrients and shortened significantly the whole process. Cooking soya bean and kidney bean seeds with electric and induction stoves facilitated better protein preservation in comparison to the thermal treatment performed in a combined micro-wave oven.