Hyaluronan (HL), a naturally occurring glycosaminoglycan, has been chemically modified through the esterification of its carboxylic groups with different types of alcohol. The physico-chemical properties of these new biopolymers allow the preparation of many biomaterials which may be used in several medical applications. In the present study both the biocompatibility and biodegradation of some water-insoluble HL esters have been evaluated, either as raw material or as manufactured devices after subcutaneous and intraperitoneal implantation in male rats. The inflammatory response and the degree of resorption for each tested material are reported. The relationships between the degree of esterification and the type of alcohol used with the above parameters are also investigated.