Serotonin reuptake inhibitors (SSRI), such as venalafaxine and paroxetine, are used in the treatment of generalized anxiety disorder (GAD). Patients with GAD frequently have comorbid psychiatric disorders, such as depression. SSRIs are effective in the treatment of a variety of anxiety disorders and depression. Citalopram, a newer SSRI used in the treatment of depression, has not been studied for GAD. This is the first report of the use of citalopram, the most selective SSRI, for the treatment of GAD in a retrospective case observation study. Thirteen patients diagnosed with GAD were treated with citalopram at an academic outpatient clinic. The main outcome measures were the Hamilton Rating Scale for Anxiety (HAM-A), Hamilton Depression Rating Scale (HAM-D) and Clinical Global Impressions of Severity (CGI-S; at baseline) and Improvement (CGI-I). The mean age of the patients was 38 years. The mean dose of citalopram at endpoint was 33 mg/day (range 10-60 mg/day). After 12 weeks of treatment with citalopram, all 13 patients experienced full or partial improvement in GAD and depressive symptoms leading to meaningful improvement in social and occupational functioning. Mean baseline HAM-A scores (mean+/-SEM) decreased from 22.2+/-1.3 to 6.2+/-0.9 after citalopram treatment. The mean CGI-I score was 1.8+/-0.2 with 11 of the 13 patients responding (CGI-I of 1 or 2). These data suggest that citalopram may be an effective treatment for GAD. Several patients who had failed previous treatment with other SSRIs responded to citalopram, suggesting that a second SSRI, such as citalopram, may be beneficial in this population. A larger placebo-controlled study of citalopram is warranted in GAD.