OBJECTIVE We examined the impact of intensive versus conventional diabetes treatment upon menopause among women with type 1 diabetes in the Diabetes Control and Complications Trial (DCCT), a randomized controlled trial of intensive diabetes treatment, and its observational follow-up, the Epidemiology of Diabetes Interventions and Complications (EDIC) study. RESEARCH DESIGN AND METHODS In a secondary analysis of women in the DCCT/EDIC (n = 657), outcomes were the cumulative incidences of natural menopause and surgical menopause. Cox regression analyses were used to examine associations with treatment group, time-varying estimates of hemoglobin A1c (HbA1c), insulin dosage, BMI, and microvascular complications (retinopathy, nephropathy, and neuropathy). RESULTS By EDIC year 18, after an average of 28 years of follow-up, 240 (38%) women had experienced natural menopause and 115 (18%) women had experienced surgical menopause. Age at natural menopause was similar in the intensive versus conventional groups (49.9 vs. 49.0 years; P = 0.28), and age at surgical menopause was similar in the intensive versus conventional groups (40.8 vs. 42.0 years; P = 0.31). In multivariable models, treatment group, HbA1c, and microvascular complications were not associated with risk of natural or surgical menopause. Each 10 unit/day increase in insulin dosage decreased risk of natural menopause (hazard ratio [HR] 0.91, 95% CI 0.75-0.98) and each kg/m(2) increase in BMI increased risk of surgical menopause (HR 1.08, 95% CI 1.00-1.16). CONCLUSIONS In the DCCT/EDIC, intensive versus conventional treatment group and HbA1c level were not associated with menopause risk. Greater insulin dose was associated with lower menopause risk.