BACKGROUND: Psychological disorders, including depression, are common in adults with asthma. Although depression is treatable, its impact on longitudinal asthma outcomes is not clear. OBJECTIVE: To elucidate the impact of depressive symptoms on patient-centered outcomes and emergency health care use in adults with asthma. METHODS: We conducted a prospective cohort study of 743 adults with asthma who were recruited after hospitalization for asthma. Depressive symptoms were defined as having a score of 16 or more on the Center for Epidemiologic Studies Depression Scale. We examined the impact of depressive symptoms on patient-centered outcomes (validated severity-of-asthma score, Marks Asthma Quality of Life Questionnaire, and 12-Item Short-Form Health Survey physical component summary score) and on future emergency health care use for asthma ascertained from computerized databases. RESULTS: The prevalence of depressive symptoms was 18% (95% confidence interval [CI], 15%-21%) among adults with asthma. Depressive symptoms were associated with greater severity-of-asthma scores after controlling for age, sex, race/ ethnicity, educational attainment, and cigarette smoking (mean score increment, 2.6 points; 95% CI, 1.8-3.4 points). Furthermore, depressive symptoms were associated with poorer asthma-specific quality of life (mean score increment, 19.9 points; 95% CI, 17.7-22.1 points) and poorer physical health status (mean score decrement, 3.7 points; 95% CI, 1.5-5.8 points). Depressive symptoms were associated with a greater longitudinal risk of hospitalization for asthma (hazard ratio, 1.34; 95% CI, 0.98-1.84). After controlling for differences in preventive care for asthma, the relationship was stronger (hazard ratio, 1.45; 95% CI, 1.05-2.0). CONCLUSION: Depressive symptoms are common in adults with asthma and are associated with poorer health outcomes, including greater asthma severity and risk of hospitalization for asthma.