To determine nationally representative estimates of the prevalence of depressive symptoms and factors associated with treatment among those with moderate to severe symptoms.A cross-sectional, retrospective analysis of adults age≥18 years in the 2005-2010 National Health and Nutrition Examination Survey data who responded to the Patient Health Questionnaire (PHQ-9) was conducted (n=13,320). Depressive symptoms and severity were defined by PHQ-9 scores. Depression treatment was defined as either receiving antidepressants or seeing a mental health professional. Multivariable logistic regression analyses using population weights identified factors associated with having depressive symptoms and receipt of any treatment.The prevalence of depressive symptoms increased from 20.92% to 25.66% over 6 years. Among patients with moderate to severe depression, 38.66% received treatment. Multivariable analyses found that being female, other Hispanic, younger age, having certain chronic comorbidities or previous hospitalization, no health insurance and in poverty status were associated with having depressive symptoms (P<.05). Among patients with moderate to severe depression, being female, white, younger age, having comorbidities (arthritis and hypertension) or previous hospitalization were associated with receipt of treatment (P<.05).The prevalence of depressive symptoms is high, and only a small portion of patients with moderate to severe depression received treatments. Treatment disparities exist and need improvement.