The aim of this study was to reduce the level of homocysteine (Hcy) by high-methionine dietary supplementation of folic acid and to evaluate changes in lipid parameters in blood serum of experimental rats. The animals were randomly divided into seven groups (n=6, male), and were fed seven different diets for 52 days. The rodents were fed with the AIN-93G semi-synthetic diet (group I), supplemented with 32 g of methionine/kg diet (group II), whereas groups III-VII were fed with AIN-93G semi-synthetic diet supplemented with 32 g of methionine/kg diet and 2, 4, 8, 18 and 28 g of folic acid/kg diet, respectively. Contents of of homocysteine, total cholesterol level, HDL fraction and triacylglycerols were assessed enzymatically in rats serum. In addition, the LDL+VLDL cholesterol content was calculated. Folic acid content in the diet was found to be highly negatively correlated with homocysteine content (r=-0.95) and negatively correlated with triacylglycerols content (r=-0.94) in the serum of rats. In the serum of rats which were fed the methionine diet with the highest-folic acid supplementation (28 mg folic acid/kg diet), homocysteine and triglyceride contents were significantly lower, compared to animals fed other types of experimental diets.