Licensed under a Creative Commons Attribution 4.0 International License Genetically modified (GM) maize and conventional maize were tested experimentally to determine their effect on chicken serum biochemical parameters and metabolism. A total of 600 one day old parent stock chickens of breed White Plymouth Rock were divided into 2 experimental groups: K -diet based on traditional maize (control); D -a diet based on GM maize (experimental). During the experimental period (17 weeks), population vibility and feed consumption were monitored daily. At the age of 4, 8 and 17 weeks all birds were individually weighed. Blood samples for biochemical analyses were collected from chickens at 4 weeks and 12 weeks of age (n = 6). Analytical studies did not show significant changes in biochemical serum parameters in group D chickens. A significant difference between the groups of chickens receiving GM and traditional maize was found only by the content of lipids after 4 weeks (P <0.05) and cholesterol after 12 weeks of the experiment (P <0.05). Also noted increasing level of circulating immune complexes in serum of chickens that consumed feed from GM maize relative control at 32.2% (P <0.05) after 4 weeks of the experiment. However, the studied indicators of metabolism and immune response in birds were within the physiological range. Certain fluctuations in the parameters during the experiment were observed in both groups, which indicates that there is no connection between this fact and the feeding factor. In addition, optimal results were obtained in terms of feed conversion and body weight of poultry, regardless of the feeding ration. The body weight of chickens at the age of 17 weeks in both groups was in the range of 1,862.4-1,895.6 g, feed consumption per 1 kg of body weight gain was 3.65-3.76 kg, the livestock viability -96.6-97.3%. The results of the study do not indicate any danger to the metabolism and health of the bird due to the use of genetically modified feed, as no statistically significant differences within the studied parameters were observed. The noted certain small deviations fell within the limits of normal variations of the considered indicators and, thus, had no biological or toxicological value.