W-B-C system composites were prepared by arc melting in an argon atmosphere using B₄C, WC, WB, B and C powders. Lamella textures indicating eutectic reaction were observed at B₄C contents of about 20mo1% and l0mol% in the quasi-binary W₂B₅-B₄C and WB₄-B₄C systems, respectively. Carbon phase in the W₂B-B₄C-C ternary system was needle-like. The Seebeck coefficient (α) generally decreased with increasing W₂B₅ and WB₄ contents. However, the W₂B₅-B₄C composites containing 2mol%W₂B₅ have slightly greater α values than those of B₄C in the temperatures range between 200 and 1000K. The electrical (σ) and thermal conductivities (K) increase with increasing W₂B₅ and WB₄ contents. The figure of merit values (Z) increased with increasing temperature. The W₂B₅-B₄C composites containing 2mol%W₂B₅ showed slightly greater Z values than B₄C at temperatures between 200 and 1000K. The highest ZT value at T=1000K was about 0.1.