Laser induced conversion of methane into methanol over WO3, TiO2 (rutile) and NiO semiconductor photocatalysts, at room temperature, under the irradiation of a strong UV laser beam at 355 nm has been studied for the first time. In addition to monitoring the yield of the targeted product methanol, the yield of hydrogen, produced as by-product, was also monitored. The comparison of the amount of hydrogen produced in the presence and absence of methane was used to assess the mechanism of degradation of methanol immediately after its formation in the aqueous suspension. (C) 2004 Elsevier B.V. All rights reserved.