The aim of this diploma thesis was to analyse differences in drying of reaction wood and normal wood of spruce and to determine differences in density, moisture content, moisture gradient and covering, distribution of temperature, longitudinal shortening and colour difference between reaction and opposite wood. The work in the first chapter characterizes the reaction wood in general and further focuses only on compression wood, describes its structure at various levels and compares selected physical and mechanical properties of reaction wood and normal wood of spruce (Picea abies /L./ Karst) or coniferous wood in general. The second chapter describes the selection of the material for the experiment, the preparation of the samples, the used equipment, the drying modes and the way the individual measurements of the described properties were determined. The third chapter presents the measured data and the results obtained in the form of tables, graphs and discussion. In conclusion, the results of the thesis are summarized. This work has confirmed that the density of the reaction wood is higher due to thicker cell walls. Furthermore, it was found that the initial moisture content of reaction and opposite wood was at the same level, but the reaction wood was dried more slowly and reached higher values of the final moisture content than the opposite wood. There was also found bigger moisture gradient of reaction wood before and after drying. When comparing covering, lower values were found in the reaction wood, only after high temperature drying the ratio between reaction wood and opposite wood were similar. When comparing the temperature distribution in the individual layers of the wood, a faster heating of the middle layers of the opposite wood was found in the section above and below the fibre saturation point, only during high temperature drying the reaction wood heated faster below the fiber saturation point. Higher longitudinal shrinkage of the reaction wood was also found, and when the color change due to drying is compared, bigger color changes were observed in the opposite wood, which is naturally lighter in comparison with the reaction wood and its tracheids absorb less light. Since the spruce is our second most widespread wood and at the same time the most economically significant, a thorough knowledge of the properties and differences in the drying of reaction wood and normal wood can have a positive impact on its processing and the wood industry in general.