Stigma of mental illness is a major obstacle to its diagnosis and treatment and may be worse among Asians than Caucasians. This study compared the stigma of depression in 50 Chinese Americans (CA) and 50 Caucasian Americans (WA). Subjects were asked to read 5 case vignettes in the following order: diabetes mellitus (DB), major depressive disorder (MDD), somatoform depression (SD), psychotic depression (PD), and fever of unknown origin (HA). Diagnosis of each case was not revealed. Subjects then rated their response to each case, on a Likert scale from "strongly disagree" to "strongly agree," to 25 statements that contained 6 stigma factors: fear, shame, cognitive distortion, social consensus, discrimination, and sanction. Composite scores constructed from ratings of each factor were used to calculate the severity of stigma. Stigma of all 5 cases was worse in CA than WA. Both groups ranked DB and HA to be least and PD to be most stigmatizing. CA rated SD to be less stigmatizing than MDD but not WA. We concluded that stigma formation and severity were determined by fear, shame, cognitive distortion, social communication, consensus, and sanction. Mental symptoms, particularly psychotic symptoms, were more stigmatizing than physical symptoms, especially for CA. Belief that depression was like a physical illness did not diminish its stigma.