Two studies of Puerto Rican youths' development on the U.S. mainland examined the consequences of perceived racial/ethnic discrimination on mental health. In Study I, children were found to have a low likelihood of perceiving discrimination, whereas in Study 2, nearly half of the adolescent sample reported perceiving racial/ethnic discrimination. Although both groups scored high on multiple indicators of mental health, perceiving discrimination and worrying about discrimination were negatively associated with some dimensions of self-esteem and positively associated with depression and stress. Adolescents were aware of negative stereotypes about Puerto Ricans, and nearly half of them related discriminatory instances. Results suggest that both perceiving discrimination and anxiety regarding discrimination can serve as risk factors for the mental health of this population.