Present status and future prospect of microgravity combustion research in Japan and USA are introduced. Since combustion phenomenon is strongly affected by gravitational force, microgravity has been played important roles in all research areas of combustion, gaseous combustion, liquid combustion and solid combustion. In the next decade contribution to energy and environmental problem and material science through microgravity combustion research will be important as well as fundamental research for fire safety for long-term manned space missions.