In this study, carbon materials were obtained from oak wood, a lignocellulosic biomass, by hydrothermal carbonization. The characterizations of the obtained carbon materials were performed by Fourier transform infrared (FT-IR), elemental analysis, Brunauer - Emmett - Teller (BET) surface area and scanning electron microscopy (SEM) techniques. High temperature and long reaction times increased the degree of carbonation. The highest carbon content of HTC was found to be 70.80% in 72 hours at 225 degrees C. While the oxygen content of the raw material is 47.36%, the oxygen content of HTC is much lower than the raw material. The lowest oxygen content was found to be 24.04% at 225 degrees C for 72 hours. The higher heating value (HHV) was calculated as 16.59 MJ / kg for the raw material and 21.05-28.30 MJ / kg for HTCs. The FT-IR spectra show that oxygenated functional groups in the structure are preserved. BET surface areas of HTC's range from 15 to 23 m(2)/g. When the surface morphology is investigated, the total surface can be divided into two main regions: fibrous structures and heterogeneous spheres. There is a marked increase in microsphere diameters as temperature and reaction time increased.