The clinical outcomes of percutaneous coronary intervention (PCI) in patients with dialysis are still worse compared with those without dialysis. Among patients with dialysis, those who started dialysis due to diabetic nephropathy (DMN) may have a worse prognosis than those who started dialysis due to non-DMN. This retrospective study aimed to compare the clinical outcomes in dialysis patients who underwent PCI between with and without long-term dialysis due to DMN. We included 303 dialysis patients with PCI. The length of dialysis at the time of PCI was used to stratify the study patients. Patients with DMN and the length of dialysis ≥ 3 years were defined as the long-DMN group (n = 117), and the others were defined as the other group (n = 186). The primary endpoint was the incidence of major adverse cardiac events (MACE), which was defined as a composite of all-cause death, non-fatal myocardial infarction, re-admission for heart failure, and ischemia-driven target vessel revascularization. A total of 165 MACE were observed with the median follow-up of 568 days. The Kaplan-Meier curves showed that MACE was more frequently observed in the long-DMN group than in the other group (p = 0.005). In the multivariate Cox hazard model, long-DMN was significantly associated with MACE (hazard ratio 1.483, 95% confidence interval 1.075-2.046, p = 0.016) after controlling for multiple confounding factors. Among patients with dialysis, the combination of DMN and a long history of dialysis is closely associated with poor clinical outcomes. These patients should be carefully followed up by both cardiologists and nephrologists.