Background: Burden related to major depressive disorder (MDD) derives mostly from long-term occurrence of symptoms. This study aims to examine the prevalence, sociodemographic correlates, patterns of 12-month and lifetime psychiatric comorbidity, lifetime risk factors, psychosocial functioning, and mental health service utilization of chronic major depressive disorder (CMDD) compared to nonchronic major depressive disorder. Methods: Face-to-face interviews were conducted in the 2001–2002 National Epidemiologic Survey on Alcohol and Related Conditions (n = 43,093). Results: The 12-month and lifetime prevalence of CMDD within the population meeting criteria for MDD was 26.5% and 24.0%, respectively. Individuals reporting a chronic course of MDD were socioeconomically and educationally disadvantaged, tended to be older, report loss of spouse or history of divorce, live in rural areas, have public assistance, low self-esteem, worse overall health and more likely to report comorbidities, most importantly dysthymia, generalized anxiety disorder, avoidant, and dependant personality disorder. Individuals with chronic MDD were more likely to report familial but not childhood onset risk factors for MDD. Those suffering CMDD were more likely to seek and receive mental health care than other forms of MDD, even though it took longer to start treatment. Conclusion: Chronic course of MDD is related to still worse socioeconomic conditions, educational achievement, more comorbidities, and family risk factors, although other courses of MDD carried greater risk of unmet treatment. Depression and Anxiety, 2011. © 2011 Wiley-Liss, Inc.