Up to the seventies the biogas has been rarely utilized. It started to be utilized on a large scale as a source of energy after 1973 when the prices of fuels and energy went rapidly up. In the paper the USA experience in this branch, which has been gained up till now, is presented, the following problems are discussed: the choice of a proper technology tor the combustion of biogas, I.C. engines operated with biogas, application of these engines in the sewage-treatment plants and biogas-fed boilers. The experience gained by the American engineers can also be applied in Poland.