This paper describes the enzymatic hydrolysis of olive mill solid residue (OMSR) in a continuous membrane bioreactor (CMB) which was equipped with an ultrafiltration membrane (Carbosep M5) of 10 kDa molecular weight cut-off. Enzymatic hydrolysis of OMSR made it possible to obtain a saccharification yield of about 45% after an experimental time of about 14 h, while a batch reactor required 24 h. It was determined that the Trichoderma reesei had a greater affinity for the OMSR substrate in a CMB than in batch mode. It was also observed that the inhibitory effects were not encountered in CMB with substrate concentrations 2.5 times greater than the concentration obtained in the batch bioreactor in which inhibition was reached.