The article is focused on potential utilization of catalysts in tar removal from biomass gases. In the theoretical part it deals with the use of catalytic purification and application of reforming and prereforming catalysts. The processes occurring on the catalyst and their mechanisms including carbon formation and catalyst deactivation are described and minimization of the undesirable processes is discussed. A laboratory method for selection of an appropriate catalyst is described in the experimental part. Several commercially available reforming and prereforming nickel catalysts were tested. In application of classic reforming catalysts, temperatures higher than 700 ^oC and steam excess must be used to minimize deactivation. If the gas does not contain sulfur compounds and catalyst regeneration proceeds in the catalytic unit, active prereforming catalysts can be already used at 450 - 550 ^oC.