The sous-vide method is an example of hydrothermal treatment that is beneficial in terms of preserving the nutritional value and the unique sensory quality of Cruciferous vegetables. That technique includes vacuum packing, heat treatment, and, then, immediate cooling  of a product. The use of hermetic packaging provides many benefits not only during cooking but, also, during storing and transporting.  Due to the increasing popularity of the sous-vide method, it is essential to know how this method impacts the nutritional value of food  products from the point of view of nutrition. The objective of the research study was to compare the impact of sous-vide cooking with the  effect of other traditionally applied methods of thermal processing of Cruciferous vegetables, such as: white cauliflower, Brussels sprouts,  Romanesco cauliflower, and broccoli, on the content of selected nutrients and dietary fibre. Immediately following the thermally  treatment, the vegetables were chilled and stored for 5 days at a controlled temperature of 2 ÷ 3 ºC in hermetic packages. In the  vegetables, there were determined the contents of dry matter, protein, fat, ash, total dietary fibre and its soluble fraction. The results of the analyses performed indicate that applying the thermal treatment of cruciferous vegetables significantly impacted their nutritional value.  Compared to the traditional cooking in water, the sous-vide cooking, as well as the steaming, was more beneficial in terms of the  nutritional value of vegetables. Moreover, compared to other techniques, the sous-vide method made it possible to retain the highest  amount of dietary fibre, including its soluble fraction.