The present review paper highlights on the recent progress in Japan on the hot gas cleanup of HCl, H 2 S and NH 3 in raw fuel gas for coal-based, combined cycle power generation technologies. It has been shown that NaAlO 2 , prepared by mixing Na 2 CO 3 solution with Al 2 O 3 sol, can reduce HCl in an air-blown gasification gas from the initial 200 ppm to <1 ppm at 400 °C, and it is tolerable for 200 ppm H 2 S. With regard to the removal of H 2 S, studies on the stability and durability of ZnFe 2 O 4 sorbent in a simulated fuel gas have indicated the presence of an optimal operation temperature from the viewpoint of the suppression of both vaporization of metallic Zn and carbon formation from CO. High-performance TiO 2 -supported ZnFe 2 O 4 , which can decrease 1000 ppm H 2 S to <1 ppm at 450 °C and 1 MPa, has been developed by the homogeneous precipitation method using a mixture of SiO 2 sol and an aqueous solution of Zn and Fe nitrates, followed by mixing with TiO 2 . Although this sorbent is regenerable and durable, the sorption ability should be improved in a syngas-rich fuel gas from an O 2 -blown gasifier. A novel method to prepare carbon-supported ZnFe 2 O 4 and CaFe 2 O 4 by impregnating the corresponding nitrate solution with brown coal has been proposed, and the large desulfurization capacity of almost 100% has been achieved in the removal of 4000 ppm H 2 S around 450 °C. The present authors have demonstrated that an Australian limonite rich in α-FeOOH is practically feasible as the catalyst material for the decomposition of 2000 ppm NH 3 in a syngas-rich gas of 25 vol.% H 2 /50 vol.% CO at 750 °C, because small amounts of H 2 O and CO 2 added to the gas can work efficiently for inhibiting carbon deposition from the CO.