Abstract This paper presents an overview of biogas compositions originating from agriculture and the organic fraction of municipal solid waste. An intensive data compilation was performed from literature, plant data from an EU project (Waste2Watts) and from sampling campaigns at 5 different anaerobic digesters in Switzerland. Besides reporting the major components of biogas i.e. methane and carbon dioxide, the concentration of minor components such as nitrogen and oxygen, as well as trace amounts of sulfur compounds (H2S, mercaptans, sulfides, etc.), silicon compounds (siloxanes, silanes), ammonia, halogenated compounds, and other volatile organic compounds (VOCs) are reported. These trace compounds can present a significant challenge to the energetic use of biogas, specifically in the use of novel, high-efficient processes such as high temperature fuel cells or catalytic fuel upgrading units. H2S and other sulfur compounds are the major concern, as they are abundantly found in agriculture biogas; unlike silicon compounds, which are generally exist in low or undetectable levels.