The importance of an APOAV gene for plasma triglyceride level determination has been shown on transgenic and knockout mice. We examined whether APOAV variants are associated with plasma triglyceride levels and risk of myocardial infarction (MI). We have evaluated the influence of APOAV polymorphisms (T-1131>C and S19>W) on plasma triglycerides in 1191 males and 1368 females representatively selected from the Czech population. Triglycerides have been analysed in 1997 and 2001. Subsequently, we have analysed the genotype frequencies of the APOAV polymorphism in 435 patients with MI. T-1131>C variation in the APOAV gene affects the plasma triglyceride showing a higher level in C-1131 carriers than in T/T-1131 homozygotes. This association has been observed both in males and females (p < 0.001). Similarly, plasma triglycerides were also significantly influenced by the S19>W APOAV genotypes. In both males and females, the W19 carriers have triglycerides significantly (p < 0.001) higher compared to the S19 homozygotes. In a group of MI patients, the frequency of the rare homozygotes for at least one APOAV polymorphism (C/C-1131 and/or W/W19) was significantly higher than that in the population sample (7.4 vs 2.0%, p < 0.00001). We conclude that variations in the APOAV gene not only play a role in genetic determination of triglyceride levels but also could influence risk of MI.