In this paper, the authors determined the usefulness of Agaricus bisporus, classified as a second class quality (as required by the Polish Norm), in the production of frozen and canned stuffings. Prior to chopping and preserving the mushrooms, they were blanched in water or in solutions of sodium metabisulfite, citric acid or L-ascorbic acid, or soaked in the solutions as described above, and, then, blanched in water. Owing to this pretreatment type, there was an decrease in dry matter, ash, total N, and total acidity contents. The reduction levels were higher in the soaked and blanched material if compared with the material that was just blanched. After canning, subsequent decreases were noted. If freezing the stuffings, no effect on the components under investigation was stated. The frozen and canned stuffings contained 5.66-8.41 g of dry matter, 0.05-0.08 g of total sugars, 0.25-0.39 of total nitrogen, 0.50-1.05 g of ash, and 0.76-1.29 cm³ 1M NaOH of total acidity per 100 g of product. The products showed a good organoleptic quality (4.44 – 4.65 points on the 5-point scale).