This study examined associations between medications prescribed to control children's problem behaviors and levels of, and diurnal variation in, salivary cortisol (C), testosterone (T), and dehydroepiandrosterone (DHEA). Saliva was collected in the morning, midday, and afternoon from 432 children ages 6-13 years. Relative to a no-medication comparison group, children taking (1) antipsychotics had higher DHEA levels and flat C diurnal rhythms, (2) Ritalin[R] or Adderall[R] had flat T diurnal rhythms, (3) Concerta[R] had higher T and DHEA levels, (4) antidepressants had flat DHEA diurnal rhythms, and (5) hypotensives had flat DHEA diurnal rhythms and higher T levels. Medications prescribed to control children's problem behaviors should be monitored in studies of the endocrine correlates and consequences of developmental psychopathology.