The nutritional value of animal feed primarily depends on its chemical composition (content of crude protein, crude ash, crude fibre, crude fat and nitrogen-free extracts), which is to some extent determined by fertilization with sulphur. The aim of the study was to evaluate the effect of different sulphur application regimes on selected quality parameters of cocksfoot Dactylis glomerata L. A field experiment was conducted on brown eutrophic soil. Sulphur was applied in two doses: 10 kg S ha-1, and 20 kg S ha-1. In addition, each experimental treatment was fertilized with 120 kg N ha-1, 30 kg P ha-1, 100 kg K ha-1, and 15 kg Mg ha-1. During the growing period from March to September, air temperature and precipitation were monitored. Fertilization with sulphur was found to affect the content of crude fibre, crude ash, crude fat, cystine and methionine in cocksfoot, while no correlation was observed between the content of these chemical components and the weather conditions. The concentration of nitrogen-free extracts did not vary significantly in response to sulphur application, but the content of these compounds correlated with the average precipitation sum, air temperature, and Selyaninov’s coefficient. Sulphur application did not affect the crude protein content, which was significantly correlated with the temperature and Selyaninov’s coefficient during the growing season of cocksfoot. The results of the field experiment suggest that sulphur fertilization of cocksfoot increased the quality of the fodder.