The research was conducted during 2015–2018 in the conditions of the V.M. Remeslo Myronivka Institute of Wheat National academy of agrarian sciences of Ukraine (Forest-Steppe) and the Nosivska Plant Breeding and Experimental Station (Polissia). The research was carried out in accordance with conventional methods and guidelines. Weather conditions were contrasting, namely optimal in 2015/16, arid in 2016/17 and excessively humid — 2017/18. It was found that they significantly affected protein content. Thus, the largest one was formed in 2016/17, when in the period from the beginning of milk state of grain to the end of wax ripeness the hydrothermal coefficient (HC) was 0.7. Less protein content was formed in 2015/16 and 2017/18, when cool weather with high humidity was observed during grain filling. The protein content of the varieties was in the range of min 8.20 and max 12.95% in the ForestSteppe, min 8.10 and max 11.80% in the Polissia. In 2017/18, in the conditions of Polissia there was observed a phenomenon when gluten content was slightly lower at almost the same protein content in the varieties studied as compared with its content in these varieties in the Forest-Steppe zone. During the period from full ripeness to harvesting varieties in Polissia and Forest-Steppe in 2017/18 HC = 4.2 and 2.5, respectively. Wheat varieties have formed on average for three years gluten content in the range of min 20.18 and max 26.09% in the Forest-Steppe, min 15.50 and max 30.0% in the Polissia. There were found moderate correlation r = 0.56 between grain protein and gluten content for the varieties studied in the Forest-Steppe zone and strong correlation r = 0.85 in the Polissia zone. The ratio of gluten to protein in winter wheat grain on average varied from 1.7 in some points of climatic conditions of the ForestSteppe and Polissia in 2015/16 for the variety MIP Valensiia to 2.7 for the variety Hratsiia myronivska in the Forest-Steppe zone in 2016/17 and for the variety Horlytsia myronivska in the Polissia zone in the same year. The impact of the factor «variety» on protein content was 19%, interaction of factors «variety — year» was 15%, the influence of the factor «year» on gluten content in winter wheat grain was the maximal — 41%, the interaction of factors «variety — year» was 14%. Weather conditions of winter wheat cropping season, especially during grain formation, significantly affected the quality indices. They are formed the best under moderate supply of plants with moisture to and worse — with excessive moisture. Increase in gluten mass fraction significantly depended on the conditions of the year and varietal characteristics