Abstract <p>Titanium carbonitride was synthesized for the first time in a closed reactor (constant pressure bomb) from granular mixtures Ti + 0.5C and TiC + Ti. Changes in sample mass, titanium carbide particle size, and granule size had a weak effect on the phase composition of the product. As in the case of synthesis of powder charge, the determining factor for increasing the nitrogen content in titanium carbonitride was an increase in nitrogen pressure. Chemical analysis showed that the product obtained from Ti + 0.5C granular mixture at a pressure of 16 atm contains 5.1% nitrogen, which is close to 6% in titanium carbonitride synthesized from bulk-density powder charge. Replacing Ti + 0.5C with TiC + Ti led to an increase in the nitrogen content to 9% for both granular and powder mixtures. Thus, the nitrogen content in products synthesized in a constant pressure bomb at 4–16 atm was independent of green mixture structure. According to XRD data, the product with composition close to TiC_0.5N_0.5 was obtained from more massive TiC + Ti granular mixture, which is associated with a longer cooling time. In contrast to the synthesis from powder mixtures, titanium carbonitride granules were easily crushed into powders.</p>