Data on the prevalence and co-occurrence of multiple somatic symptoms among US adolescent females as they are influenced by sociodemographic, behavioral, and environmental factors is limited. To describe the health status of adolescent US females measured by the prevalence, frequency, and co-occurrence of headache, stomachache, backache, and morning fatigue and to investigate associations between selected risk and protective factors. School-based, cross-sectional, nationally representative survey of adolescents in the 6th through 10th grades in the US. Data collected between 1997 and 1998. Prevalence of headache, stomachache, backache, and morning fatigue. Among US adolescent girls, 29.1% experience headaches, 20.7% report stomachaches, 23.6% experience back pain, and 30.6% report morning fatigue at the rate of more than once a week. Co-occurrence of somatic complaints is common. Among girls who experienced headaches more than once a week, 3.2 million (53.3%) also reported stomach pain more than once a week and 4.1 million (74.3%) reported morning fatigue more than once a week. Heavy alcohol use, high caffeine intake, and smoking cigarettes every day were strongly associated with all symptoms, while parent and teacher support served as protective factors. Somatic complaints of headache, stomachache, backache, and morning fatigue are common among US adolescent girls and co-occur often. Effective clinical treatment of this population requires comprehensive assessment of all female adolescents presenting with seemingly isolated somatic complaints.