Transition metal carbides (TMCs) have attracted great interest owing to their potential applications for energy storage and electrocatalysis. But the synthesis of high-quality TMCs usually needs high energy consumption, long reaction times, or dangerous chemical reagents, limiting their practical application. Here, a microwave combustion method is developed to rapidly (∼2 min) produce transition metal carbides under ambient conditions. The as-synthesized TMCs (W2C, VC, Fe3C, NbC, TaC, and Mo2C) and rGO composites exhibit outstanding catalytic performance for the hydrogen evolution reaction (HER) over a broad range of pH values. This work highlights a novel strategy for the design and synthesis of transition metal carbides.