Apolipoprotein CIII is a major protein component of chylomicrons and very low density lipoproteins (VLDL) and it is important in the regulation of triglyceride metabolism. Sst 1 polymorphism in the apolipoprotein CIII gene (APO CIII) has been recognized as a factor influencing levels of plasma triglycerides. We examined APO CIII Sac I (Sst I) variants and serum lipids profile in 175 subjects. DNA samples were analyzed by polymerase chain reaction (PCR) followed by Sac I (Sst I) digestion. The frequency of S2 allele was found to be three times higher among men with enhanced plasma triglyceride (TG) compared to men with normal TG levels (16,2% vs. 5,2%). Subjects with the S1S2 genotype compared to S1S1 homozygotes had higher plasma triglycerides and cholesterol levels (190 ± 155 mg/dl vs. 139 ± 90 mg/dl, p=0,035; 234 ± 60 mg/dl vs. 214 ± 37, p=0,04 respectively). These results indicate that a relationship between S2 allele of APO CIII gene and enhanced TG levels occur in studied population.