The aim of the study was a comparison of biochemical and hematological indices in turkeys’ blood from intensive and proecological breeding systems. The experiment was performed on 60 middle-heavy turkeys’ males, which were kept to the age of 19 weeks. After six weeks they were randomly allocated to two groups. The control group was reared in intensive poultry production system according to the technology of industrial breeding. The second group was reared in proecological system; it was fed “ad libitum” on noncommercial farm fodders. At the end of rearing during the slaughter samples of blood were collected from neck vein (vena jugularis) of turkeys. Values of hematological and biochemical indices and content of mineral components were established by clinical methods. In the group of turkeys bred by proecological system statistically significant growth of hematological indices level was ascertained relatively to control group from intensive system. In the group where the balanced fattening was employed the increase of aminotransferase activity, decrease of cholesterol and uric acid level, and a reduction of content of phosphorus and iron in turkeys’ blood were also observed. Maintaining and feeding system had a significant influence on the level of hematological and biochemical indices in turkey’s blood.