Anaerobic digestion of sugar beet pulps was studied in a 70 l digestor with sequential feeding, after enzymatic hydrolysis by Trichoderma harzianum cellulases. During the 130 days feeding, 3.6 m3 of biogas were produced with an average content of 58% CH4 from 270 l of hydrolysed pulps at 20 g VS/l. Average yield and production rate were respectively 0.67 m3/kg VS and 0.4 m3/ kg VS and 0.4 m3/m3 of digestor per day.