The aim of the study was to assess whether the association between abdominal aortic aneurisms (AAAs) and the angiotensin-converting enzyme (ACE) DD genotype is changed in male smokers.Material and methods. The ACE I/D polymorphism was examined by PCR in 112 subjects with AAA and in 50 control subjects. The frequency of ACE genotypes (II, ID and DD) in the patient group was assessed in subgroups divided on the basis of blood pressure, smoking and sex.Results. A significant increase in the frequency of ACE DD genotypes has been found in all AAA patients studied (odds ratio OR=2.6; range 1.3-5.6, p <0.0002) when compared to the remaining ACE genotypes (ID and II) and the control group. The respective values were higher when all 74 male smokers with AAA were assessed (OR=3.6; p <0.006). No increase in ACE DD genotype frequency was seen in all females (38) and male nonsmokers when compared to the respective control group (n=16) (OR=1.4; p <0.75).In the group of normotensive AAA patients, the proportion of ACE DD genotype in relation to the remaining ACE genotypes (ID and II) was found to be higher than in the general AAA patient population (odds ratio OR=6.14; range 2.5-14.9, p <0.0001). In 32 normotensive male smokers with AAA, the respective values were higher (OR=8.3).Conclusions. An increased frequency of the ACE DD genotype in normotensive male smokers may account in large part for the increase in DD genotype occurrence noted in all AAA patients.