This article presents a state-of-the-art of atmospheric methane reconstruction based on ice-core studies. Starting with a biogeochemical overview of the methane cycle, it explains the processes of gas diffusion in firn and trapping in ice. It presents and discusses the anthropogenic impact on atmospheric CH4, and then the trend of this greenhouse gas over the last millennium, the Holocene, the last glaciation and deglaciation (including its use as a stratigraphic marker for correlating ice cores), and the last six glacial-interglacial cycles. Analytical techniques are also described. © 2007 Elsevier Ltd. All rights reserved.