Serotonin (5-hydroxytryptamine, 5-HT) is an important signaling molecule involved in numerous physiological functions, including regulation of the energy balance of the organism. The effects of serotonin are mediated by 14 different types of its membrane receptors. Serotonin receptor type 2C (5HT-2C) plays an important role in regulation of body weight and glucose metabolism and represents a pharmacological target for the treatment of obesity and control of glycemia. Wistar-Zagreb 5HT (WZ-5HT) rat is an animal model developed by selective breeding according to extreme values of platelet serotonin parameters. It consists of two sublines of the rat, hyposerotonergic (5HT-low) and hyperserotonergic (5HT-high) subline. Animals from the 5HT-low and 5HT-high sublines of the WZ-5HT rats differ significantly in body mass, adiposity, food intake, and glucose metabolism. The aim of this paper was to compare expression of the 5HT-2C receptore gene (Htr2c) between 5HT-low and 5HT-high subline of WZ-5HT rats. Expression of the Htr2c was analyzed in the hypothalamus and gonadal white adipose tissue of males from the above mentioned sublines (n = 10 per subunit) by the reverse transcription-quantitative polymerase chain reaction (RT-qPCR) method. Results of this study showed that animals from the 5HT-high subline, as compared to animals from the 5HT-low subline, had a higher relative expression of mRNA encoding 5HT-2C receptor in gonadal white adipose tissue, suggesting the potential role of this receptor in the regulation of adiposity. In the hypothalamus we did not notice statistically significant differences in the expression of the Htr2c gene between animals from the two sublines of the WZ-5HT rat, so we can conclude that hypothalamic expression of the mRNA for the 5HT-2C receptor does not contribute to the differences in the body mass regulation between these sublines.