A study on iron-deficiency anemia (IDA) in adolescence was conducted among 478 teen-age students in Shanghai. The study indicated that the intake of nutrients among the students was generally insufficient. The lack of protein, calcium, Vitamin A, Vitamin B1, and Vitamin B2 was more serious. The morbidities of IDA among male and female students were 15.8 and 32.6%, respectively, higher in the female group (P less than 0.01). The iron-deficiency sufferers among male and female students were 46.8 and 61.8%, respectively, also higher in the female group (P less than 0.01). The causes of IDA were analyzed by the method of stepwise regression. In a study of the effect of IDA on intelligence and physical development in adolescents, we found that there was no significant effect of IDA on intelligence quotient (IQ) and school performance. However, the speed and endurance capabilities of students of both sexes were correlated directly with hemoglobin level. In female students, the speed capability was correlated directly with the serum ferritin content. On the basis of these findings, a special 3-month school lunch program was initiated. The results indicate that a comprehensive, rational, and balanced diet is beneficial to hemoglobin, free erythrocyte porphyrin, and serum ferritin contents and improves adolescent development.