Background: Patients treated with dialysis or living with a kidney transplant (kidney replacement therapy, KRT) have an increased risk of bone fracture. Patients with diabetes also have an increased risk of fracture. The aim of this study was to investigate whether the presence of diabetes in patients on KRT aggravates the risk of fracture. Methods: Nationwide Danish registries were used in this retrospective cohort study. All prevalent adult patients on hemodialysis (HD) or peritoneal dialysis (PD) on 1st of January 2000 and all incident patients starting KRT (HD, PD, kidney transplanted (KTX)) until 31st of December 2011 were included in the KRT group. Adult persons not on KRT and without diabetes on 1st of January 2000 were used as a reference group. Patients were separated in groups with and without (+/−) diabetes. They were followed until first fracture, emigration, death, or end-of-study on 31st of December 2016. Results: A total of 4,074,085 not on KRT +/− diabetes and 9053 patients on KRT +/− diabetes were included. Comparing the different groups with diabetes to the corresponding group without diabetes, the unadjusted HR (95% CI) for any first fracture were 1.2 (1.0–1.3) in the HD population, 1.4 (1.1–1.7) in the PD population, and 1.7 (1.4–2.2) in the KTX population. Further adjustments for age, sex, prior fractures, comorbidity and medication did not change these results significantly. Conclusions: Diabetes increases the risk of fracture in patients on KRT.