Anaerobic digestion of organic wastes is encouraged by European regulation. It allows energy supply and recycling of organic matter and nutrients. But digestates are not fully stabilized, are rich in ammonium which can lead to ammonia emissions, and can also be odorous, too wet or too concentrated in phytotoxic volatile fatty acids, preventing a direct land application and agricultural use. Composting can be an adequate post-treatment for digestates as it can stabilize their residual organic matter. The composting behavior of different raw and digested organic wastes was studied in 300-liter pilot in order to study the influence of anaerobic digestion on the composting post-treatment. Total oxygen consumption, temperature rise and nitrogen gaseous emissions were monitored. Three types of wastes were studied: agricultural wastes, source sorted organic fraction of municipal solid wastes and mechanically sorted organic fraction of municipal solid wastes. Anaerobic digestion led logically to a decrease in organic wastes biodegradability: total oxygen consumption measured during composting was divided by three after digestion while temperature rise was limited to a maximum of 40°C for digestates. The conversion of organic nitrogen during digestion led to significant gaseous emissions during the composting of digested wastes. On conclusion, the composting of digestates must be carefully conducted. Indeed their aerobic post-treatment could lead to significant nitrogen emissions: ammonia and nitrous oxide. If it appears necessary to compost anaerobic digestion residues in order to assure their full valorization, the composting process needs to be optimized in order to achieve a minimal environmental impact.