Introduction. The broad spread of cell phones (CP) among schoolchildren and the absence of age standards for their safe use determined the purpose of the study: to reveal the regimens of CP use, critical for the health of children and adolescents. Material and methods. In a cross-sectional study in 2008-2010, by the questionnaire data of 2,137 schoolchildren aged 6-15 years there was assessed the impact of CP usage indices (daily number of calls - CN, call duration - CD, and total daily duration of calls - TCDD) on health (the incidence of headaches and sleep disorders, number of colds). Student and Mann-Whitney criteria and assessment of relative risks were used. Results. The study revealed age-dependent critical values of usage indices (in 6-10 years: CN=2, TCDD=6 minutes.; in 11-13 years: CN=6; in 14-15 years CN=6, CD=3 minutes., TCDD=4 -10 min.), the exceeding of which due to risks: in 6-10 years - to have more than 4 colds a year (OR 2.25, 95% CI 1.09-4.62); in 11-13 years to have several headaches per week (OR 1.61, 95% CI 1.12-2.30); in 14-15 years - to have several headaches (OR 1.79, 95% CI 1.27-2.54) and several sleep disorders (OR 1.66, 95% CI 1.17-2.37) per week. Discussion. Age differences in critical modes of CP use and in health violations, as well as the importance of radiation intensity are discussed. Conclusions. Age-related CP use regimens, critical for health, were established. It was shown the need to develop more precise age criteria for safe CP use with taking into account a wider range of health indicators and radiation intensity.