The treatment with NaOH and subsequent enzymatic hydrolysis of sunflower hulls was evaluated. Maximum saccharification values for sunflower hulls were reached after treatments with 0.5% alkali solutions for 1.5 h at 121 degrees C using a solid: liquid ratio of 0.1 g/ml. The hydrolysis yield increased with enzyme concentrations up to 50 FPU/g the additional enhancement with higher concentrations being hardly noticeable. IPI spite of dramatic alterations in the structure caused by the alkaline treatment, structural features seemed to remain as major hindrances to enzymatic hydrolysis.