Tencel fabrics were treated with NaOH, mechanically prefibrillated, and hydrolyzed by cellulase. Weight loss and tensile strength of the treated Tencel fabrics were evaluated under dry and wet conditions. Increase in prefibrillation time increased weight loss and decreased tensile strength retention of the treated Tencel fabrics at the same cellulase treatment conditions. Increase in concentration and treatment time of cellulase increased weight loss and decreased tensile strength retention of the treated fabrics at the same prefibrillation treatment time. At a similar weight loss, tensile strength retentions of the NaOH-pretreated fabrics were better than those of the fabrics treated without NaOH pretreatment because of more uniform hydrolysis by cellulase in the NaOH-pretreated fabrics.