Phase relations in the Ti-C-SiC system are studied with the aim of optimizing Ti3SiC2 synthesis. The optimal starting-mixture compositions for the synthesis of phase-pure Ti3SiC2 powder can be represented by the formula 3Ti + (1 - z)C + (1 + z)SiC, where z = 0.2-0.6. In the temperature range 1630-1670 K under dynamic vacuum, the excess silicon vaporizes from the sample. The processes leading to the formation of impurity phases are discussed.