Objective: Percutaneous transluminal coronary angioplasty (PTCA) in patients on maintenance hemodialysis leads to high rates of restenosis and postinterventional complications. The additional influence of diabetes mellitus on the results of PTCA in patients with diabetic nephropathy and reduced but sufficient renal function has not been investigated before. Methods: In a retrospective case-control study, 51 patients with reduced renal function were compared to 71 matched controls. Patients with elevated creatinine values were divided in two subgroups: diabetic nephropathy (diabetes, n = 15) and stable renal insufficiency (renal failure, n = 36). Results: The control group had normal renal function (creatinine: 1.0 ± 0.01) and a mean survival time of 3.6 ± 0.8 years. Patients with renal failure showed a mean survival time of 2.7 ± 0.3 years (p < 0.001), creatinine values of 2.0 ± 0.2 and elevated fibrinogen values of 401 ± 28 (p < 0.01). Patients with diabetes (creatinine: 2.2 ± 0.2) had a significantly higher mortality rate with a reduced mean survival time of 1.25 ± 0.3 years (p < 0.001), postinterventional acute renal failure (n = 2, p < 0.01) and Re-PTCA (n = 2, p < 0.05). Discussion: Patients with reduced but stable renal function showed a higher mortality than comparable patients from the control group. The group of patients with diabetic nephropathy has a poor prognosis after PTCA even though renal function was only moderately reduced.