OBJECTIVE: The prevalences of personality disorders among HIV-positive and HIV-negative homosexual men were compared, and the presence of personality disorders was related to axis I psychiatric disorders, psychiatric distress, and impaired functioning. METHOD: The subjects were 162 homosexual men who either were HIV seronegative (N = 52) or were seropositive and had absent to moderate physical symptoms (N = 110). Lifetime and current histories of DSM-III-R axis I disorders, current diagnoses of DSM-III-R personality disorders, and levels of anxiety, depression, hopelessness, and adaptive functioning were assessed. RESULTS: In both the seropositive and seronegative groups, 19% of the study participants were diagnosed with personality disorders. The seropositive participants with personality disorders reported higher levels of psychiatric symptoms and poorer functioning than all participants without personality disorders, and they were over six times as likely as the seronegative participants without personality disorders to have current axis I disorders. CONCLUSIONS: These findings indicate that HIV infection and personality disorders may interactively increase the likelihood of clinically significant psychiatric symptoms.