The pre-sonication provoked noticeable changes in the chitin morphology but its overall crystallinity was unaffected. The sonication of chitin seemed to improve its homogeneity and to increase the particles surface, enhancing the accessibility of reagents. Pre-sonicated chitin was more efficiently deacetylated (up to 95%) than commercial chitin (up to 88%) probably due to the mechanical action of ultra-sound since the previous stirring of solid chitin while suspended in hot or cold water for 1 hour also enhanced the deacetylation efficiency.