The purpose of this study was an assessment average daily intake of calcium and phosphorus by prepubertal adolescents (aged 11 and 12) during monitoring their diets in last 10 years. In 1989-1999 years, it was investigated 767 randomly selected girls and 817 boys, aged 11 and 12 in Warsaw. Information on dietary intake was obtained by 24-hour recall method, always spring, having representation of weekdays and weekends. Among environmental factors, nutrition, and particularly calcium intake is assumed to influence whether the genetically determined maximal peak bone mass is reached. However, near half of examined prepubertal adolescents have intake less than 600 mg calcium per day. It was also observed low calcium to phosphorus ratio in diets and stated Ca:P < 0.25 among 10% diet in different groups of girls and boys. Consequently, due to consider the activity educational efforts directed to prepubertal adolescent with reference to means realization of calcium RDA in daily diet through increase milk and dairy products consumption.