Summary The purpose of this study is to compare the specifics of winter and spring diets of the roe deer using rumen content analysis. A chemical analysis was performed on a total of 13 samples of roe deer rumen contents: 7 samples of winter diet rumen contents and 6 samples of spring diet rumen contents. The following parameters were examined in this study: the level of crude protein and the content of fiber (NDF, ADF and ADL). The results obtained were processed by descriptive statistics and compared using F-tests. Consequently, certain deviations in the quality of roe deer nutrition were found in both winter and spring periods of the year. A lack of protein and energy can pose significant problems to roe deer, especially in the cooler periods of the year. Approximately a total of 17MJ/day is the maximum assumed energy required for animals kept in enclosure. The need for crude protein varies from 30.8% to 34.4% DM. This problem can be tackled if roe deer are adequately fed with quality bulky and concentrated feed, despite the fact that the animals adapt metabolically to seasonal variations.