Background: Data concerning long-term mortality predictors among large, purely diabetic hemodialysis collectives are scarce. Methods: We used data from a multicenter, prospective, randomized trial among 1,255 hemodialysis patients with type 2 diabetes mellitus (T2DM) and its observational follow-up study. The association of 10 baseline candidate variables with mortality was assessed by Cox proportional hazards regression. Results: Overall, 103 participants survived the median follow-up of 11.5 years. Significant predictors of mortality were age (hazard ratio [HR] 1.03, 95% CI 1.02–1.04), cardiovascular (HR 1.42, 95% CI 1.25–1.62) and peripheral vascular disease (HR 1.55, 95% CI 1.36–1.76), higher hemoglobin A1c (HbA1c; HR 1.08, 95% CI 1.03–1.14), and loss of self-dependency (HR 1.20, 95% CI 1.03–1.39). Higher albumin (HR 0.72, 95% CI 0.59–0.89) and body mass index (BMI; HR 0.98, 95% CI 0.96–0.99) had protective associations. There was no significant association with sex, diabetes duration, and cerebrovascular diseases. Subgroup analyses by age and diabetes duration showed stronger associations of cardiovascular disease, HbA1c, albumin, BMI, and loss of self-dependency in younger patients and/or shorter diabetes duration. Loss of self-dependency and energy resources (albumin, BMI) increased mortality more severely in women, whilst the impact of cardiovascular and peripheral vascular diseases was more pronounced in men. Conclusion: Long-term mortality risk in patients with T2DM on hemodialysis was associated with higher age, vascular diseases, HbA1c, loss of self-dependency, and low energy resources. Interestingly, it does not vary between sexes. Further individualized prognosis estimation and therapy should strongly depend on age, diabetes duration, and gender.