OBJECTIVE: This study aimed to 1) measure the prevalence of sexual dysfunction in patients with diabetes; 2) describe how descriptive variables, psychological variables, diabetic complications, and sexual dysfunction relate in patients with diabetes; and 3) describe the predictors of sexual dysfunction in patients with diabetes. RESEARCH DESIGN AND METHODS: A total of 240 adult type 1 diabetic patients visiting the outpatient diabetes clinic of a university hospital completed questionnaires evaluating psychological adjustment to diabetes and sexual functioning. Medical records were used to obtain HbA(1c) values as well as information on microvascular diabetic complications. RESULTS: Sexual dysfunction was reported by 27% of women and 22% of men. No differences were found between sexes in type of reported sexual dysfunction. In men, but not in women, sexual dysfunction was related to age, BMI, duration of diabetes, and diabetic complications. No correlation with HbA(1c) was found in either sex. In women, but not in men, sexual dysfunction was related to depression and the quality of the partner relationship. Binary logistic regression demonstrated that, in men, the significant predictors of sexual dysfunction were higher age and presence of complications, whereas, in women, sexual dysfunction was related to depression. CONCLUSIONS: Both women and men with diabetes are at increased risk for sexual dysfunction. This study suggests that in men with diabetes, sexual dysfunction is related to somatic and psychological factors, whereas in women with diabetes, psychological factors are more predominant.