Acetylated chitosan sponges (chitin sponges) were prepared according to acetylation time (25, 50, 75, and 100 h). As the acetylation time increased, the degree of acetylation increased, and a 75-h acetylation time produced the highest degree of acetylation (DA). The surface morphologies of samples were examined by scanning electron microscopy. Sponge samples were shown by a water uptake ability test to have higher water absorption abilities. An in vitro biodegradation test showed that sponges with a higher DA were more susceptible to lysozyme hydrolysis. Acetylated chitosan sponges were further shown by an in vitro fibroblast proliferation test to have a higher degree of cell viability on increasing the DA, with 75 h exhibiting the maximum effect. The results showed that the wound healing effect of chitosan sponges can be controlled by the DA. (C) 2010 Wiley Periodicals, Inc. J Appl Polym Sci 117: 1618-1623, 2010