The objective of the study was to estimate the content of basic nutrients in the most popular assortments of wheat breakfast cereals. Determinations made for samples of the tested products covered the content of dry mass, total ash, total protein, and crude fat. Due to the role of dietary fibre as the main quality determinant of cereal products, the content of that component was tested with three different methods. The Weende method was employed to determine the content of crude fibre, the detergent method – to determine the content of detergent fibre (NDF – neutral detergent fibre, ADF – acid detergent fibre, HCEL – hemicelluloses, CEL – cellulose, ADL – acid detergent lignin), and the enzymatic method – that of dietary fibre (TDF – total dietary fibre, IDF – insoluble dietary fibre, SDF – soluble dietary fibre). Assays were also carried out for the content of soluble components of dry mass (water solubility index – WSI) and the water absorption index (WAI). Assortments of ready-to-eat wheat cereals (1A – 3A) and crispy wheat bread (4B) were characterised by a low protein content (from 6.2% d.m.), low content of total dietary fibre TDF (from 6.49% d.m.) and soluble dietary fiber SDF (average 3.76% d.m.), and high values of the water solubility index that reached even up to 60% d.m. Such assortments of breakfast cereals do not meet the requirements for cereal products of the base of the food pyramid due to the poor chemical composition and high content of soluble components of dry matter.