Peak bone mass (PBM) is defined as the highest bone mineral content (BMC) reached in any period of a person's life. The bone mass once gained at the peak begins to decline and continues to do so until the end of life. The aim of this study was to evaluate the relationship of nutrition and physical activity on bone mineralization during the adolescent period. The study took place at Hacettepe University Ihsan Doğramaci Children's Hospital Adolescent Unit. One hundred fourteen healthy male adolescents applying for different reasons, with ages ranging between 11.1 and 16.5 years, participated in the study. When all adolescents were evaluated, no statistical relationship between the daily calcium intake, BMC and bone mineral density (BMD) was obtained. However, a positive statistical relationship was found for those participants in Tanner stage I. This result is in support of previous studies stating the importance of calcium intake and bone mineralization in the prepubertal stage, suggested by our findings, which yielded a positive correlation only in the prepubertal stage. One of the reasons for the same effect not being observed in puberty is thought to be due to the hormonal changes and active role of sex steroids. This shows how critical the prepubertal period is for future bone health. During this critical period of prepuberty, the significance of nutritions and physical activity is evident.