The aim of this study is to assess the effectiveness of sludge pre-treatment by mean of microwave technology to improve biogas production and sanitize the treated sludge. For this purpose, the sludge was treated by microwave at different temperatures (65°, 80° and 95° C) and for different times (10 and 20 minutes), always in comparison with a conventional heat treatment (water bath). Whereas microbiological analysis showed that bacteria seem more sensitive to microwave treatment as conventional heating, the organic matter solubilization and the biogas potential of sludge seem more important after a conventional heat treatment.