Background: Autosomal dominant polycystic kidney disease (ADPKD) shows a variable clinical course suggesting that genetic modifiers might play a role. There are conflicting results about the effect of angiotensin-converting enzyme (ACE) gene polymorphism on the progression of renal failure in ADPKD. Also, the association between ACE gene polymorphism and the occurrence of left ventricular hypertrophy (LVH) has not been investigated in patients with ADPKD. Methods: ACE genotype analysis was performed in 409 Caucasian patients (137 male, 272 female) with ADPKD. Echocardiographic examination was done in 164 of these patients. Results: There were no significant differences between different ACE genotypes regarding renal function, renal volume, urinary protein excretion, blood pressure, the rate of hypertension, the age at diagnosis of hypertension, the rate of LVH and the incidence of end-stage renal disease (ESRD). Conclusion: ACE gene polymorphism does not have a significant effect on the development of ESRD and the prevalence of LVH in patients with ADPKD.