The objective of this study was to examine the influence of ACE (I/D) genotypes on recognized risk variables for hypertension and Metabolic Syndrome in two ethnic population samples from Slovakia. A total of 150 Romany subjects (68 males and 82 females) and 167 Slovaks (45 males and 122 females) were examined. They were interviewed during a medical examination and they were investigated with respect to a variety of aspects such as medical, anthropometrical and life-style. The studied subjects were defined as hypertensive if the blood pressure was > or = 140/90 mm Hg and Metabolic Syndrome (MS) was defined according to criteria of the National Cholesterol Education Program Adult Treatment Panel III-(NCEP ATPIII). ACE (I/D) polymorphism was subsequently determined by PCR amplification of the ACE gene sequence. In the entire sample, the frequency of the mutant D allele was higher in the Slovak subjects (D = 0.527) than in the Romany subjects (D = 0.447), but the difference was not significant (p = 0.053). Neither the Slovak nor the Romany normotensive and hypertensive subjects differed significantly in the distribution of the three ACE genotypes (Slovak p = 0.169, Romany p = 0.116). In both ethnic samples hypertensive men prevailed (Slovak 51.1% vs. Romany 44.1%). The features of Metabolic Syndrome were identified in both samples; they occurred in 33.3% of Slovak men and 14.8% Slovak women vs. 42.9% of Romany men and 32.4% Romany women. Regression analysis showed no association between ACE genotypes and hypertension nor between ACE genotypes and MS in these Slovak population samples.