Food intake and nutritional status were assessed in a cross-sectional study in over 1000 boys and girls aged 11-15 years from Warsaw and from a rural eastern region (Biała Podlaska province). According to qualitative criteria, about 40% of children from Warsaw and about 20% of children from the eastern region were classified as well nourished, while about 50 and 70% of children, respectively, were classified as inadequately nourished. Despite covering the daily energy demand, the content of protein in daily rations was too low, especially in the Eastern region, where protein deficiency was about 22 and 28% in boys and girls, respectively. The diets were also deficient in Ca, Mg, and vitamins B, again especially in the eastern region. Those unfavourable dietary tendencies might have contributed to the lower body height and mass observed in rural children, compared with the urban ones.