Major depression is associated with substantial psychosocial dysfunction and post-concussive symptomatology following traumatic brain injury (TBI). Studies to date of anti-depressant treatment for major depression post-TBI have been limited by small sample size. The goal of the present study is to examine the rates of response and remission associated with citalopram treatment for major depression following traumatic brain injury. Subjects with major depression following mild-to moderate TBI were treated with open-label citalopram with a starting dose of 20 mg/day to a maximum of 50 mg/day for either 6 weeks (n = 54) or 10 weeks (n = 26). The Hamilton Depression Rating Scale (HAMD) was used to assess depression severity. Response was defined by a 50% reduction in HAMD score, and remission was defined by a HAMD score of < or =7. The mean HAMD at baseline and 6 weeks were 23.66 (SD 6.8) and 16.30 (SD 9.3), respectively (t[53] = 7.157, p < 0.0001). The mean HAMD at 10 weeks was 12.96 (SD 7.9) (t[25] = 7.323, p < 0.0001). At 6 weeks, 54 subjects were assessed and 27.7% responded with 24.1% in remission. At 10 weeks, 26 subjects were assessed and 46.2% responded with 26.9% in remission. The response rate in the present sample was substantially lower than previously reported for patients with TBI, but comparable to the results of the largest effectiveness trial of citalopram for general out-patients with major depression in the absence of TBI.