The wet spinning of chitosan fibers was studied with 2% acetic acid as the solvent, 10% aqueous sodium hydroxide as the nonsolvent, and a 4% chitosan solution as the polymer. This article describes the cross-linking of the chitosan fibers. Epichlorohydrin (ECH) was selected as a convenient base-catalyzed crosslinking agent. The coagulation and cross-linking of the chitosan fibers occurred simultaneously in the coagulation bath. In this study, we investigated the effect of the concentration of the cross-linking agent, ECH, in the spinning dope on the structural, thermal, morphological, and mechanical properties (e.g., the tenacity, elongation, and work of rupture) of chitosan fibers. The tenacity of the chitosan fibers, especially the wet tenacity, was improved by cross-linking. (C) 2004 Wiley Periodicals, Inc.