Diabetes mellitus, a major health problem afflicting 500,000 Americans each year, is a leading cause of male erectile difficulties. Diabetic women may be susceptible to a similar diabetic pathogenesis for sexual problems but information about the effect of diabetes on female sexual response is sparse and conflicting. Past research has been based upon self-report measures, a methodology flawed by susceptibility to response bias. Whether diabetic women differed from a matched nondiabetic control group in their physiological as well as subjective response to erotic stimulus exposures was investigated. Vaginal photoplethysmographic measures of capillary engorgement were taken while subjects individually viewed counterbalanced erotic and non-erotic videotape presentations. Graphically and statistically analyzed results indicated that diabetic women demonstrated significantly less physiological arousal to erotic stimuli than controls, whereas their subjective responses were comparable. These objective, physiological findings support and extend previous subjectively based research which found potential diabetes-related sexual dysfunction in female diabetics. The groups did not differ, however, in the reported occurrence of sexual difficulties.