A novel microwave-assisted carbothermal reduction and carburization route has been used to prepare ZrC–SiC composite powders. Both zircon and mixtures of ZrO 2 and SiO 2 were used as starting materials along with amorphous carbon. Carbothermal reduction and carburization were examined in both argon and nitrogen atmospheres. Reaction kinetics in microwave field was found to exhibit notable differences for the two different starting materials. However, a complete oxide to carbide conversion was achieved in less than 30 min in both cases when argon was used as an ambient gas. The possible structural mechanism involved in the reactions has been discussed.