In the present paper various gasification technologies/gasifiers and syngas cleaning options are critically reviewed keeping in view various types of feedstocks and various downstream applications of syngas such as power generation, chemicals and hydrogen production, liquid fuels production and synthetic natural gas (SNG) production. Recent developments on gasification technologies including fixed bed dry bottom (FBDB) gasification, power high temperature Winkler (PHTVV) gasification, catalytic steam gasification, transport reactor gasifier as well as syngas cleanup technique including hot gas filter and warm cleaning are discussed. Techno-economic analysis of various gasifiers as well as syngas cleaning processes along with the world scenario of syngas production and its various downstream applications is also discussed. Crown Copyright (C) 2011 Published by Elsevier B.V. All rights reserved.