This study examined the extent and correlates of perceived unmet need for treatment among individuals with depression in the US general population. Analyses were based on a representative sample of 6,510 adult participants in the 2005 and 2006 National Surveys on Drug Use and Health who reported a major depressive episode in the past 12 months. A total of 3,568 (62.4%) participants had sought mental health treatment in the past 12 months, and 2,942 (37.6%) had not; 34.9% and 26.8% of these groups, respectively, reported unmet need for treatment. In both groups, older age was associated with a lower likelihood of reporting unmet need for treatment, whereas greater distress and impairment and higher education were associated with a greater likelihood of reporting unmet need. Among treatment seekers, treatment from general medical providers was associated with greater likelihood of unmet need, and more outpatient visits and insurance coverage for the full year were associated with a lower likelihood of unmet need. The most common reason for not seeking needed treatment was a concern about costs (cited as a reason by 46.0% of the total sample). Even though rates of treatment seeking have increased, many persons with major depression continue to experience unmet need for treatment, which in this study was mainly attributable to concerns about treatment costs.(Psychiatric Services 60: 297–305, 2009)