The aim of the study was to compare the properties of lipids and the content of cadmium and lead in the meat of red deer (Cervus elaphus) kept in a forest feeding ground (FFG) and on organic and conventional farms in Poland. Longissimus lumborum (LL) and Musculus semimembranosus (SM) muscles were collected for the study from 36 red deer carcasses in an equal sex and age ratio (3 and 4 years old). From April to October, the animals consumed only the vegetation growing in the feeding grounds. The floristic and phytoncide composition, as well as the fodder value, of the feeding grounds were assessed. Additionally, the intramuscular fat and cholesterol content, the profile, sum, and ratios of fatty acids (FAs), lipid nutraceutical parameters, and cadmium and lead content were determined in LL and SM. The plant composition comprised 116 species in the organic feeding ground (OFG) and 78 species in the conventional feeding ground (CFG). The LL and SM muscles of the red deer from the organic and forest feeding grounds exhibited significantly lower amounts of fat and cholesterol than those from the conventional system. The differences in the fatty acid composition between the three groups were quite small. Differences in intramuscular fat content contributed to a higher percentage of PUFAs in the FFG and OFG, in comparison to the CFG. In all types of feeding ground, the cadmium (0.002 to 0.008 mg/kg) and lead (0.009 to 0.019 mg/kg) content determined in the meat did not pose a threat to consumers.