Oxidized cellulose has a long history of safe and effective use in medical applications. In this paper, research has been directed towards obtaining hormone-active cellulose fibers in the form of an artificial insulin depot, and examination of its biocompatibility regarding cytotoxicity, sensitization, and irritation. The procedure of obtaining the fibrous insulin depot is based on the modification of cotton fibers with sodium periodate, followed by chemisorption of insulin from insulin aqueous solutions. In order to optimize the insulin chemisorption process, the influence of the fiber structure parameters, i.e. the aldehyde group content and iodine sorption value (ISV) on the chemisorption capacity was examined. The obtained artificial depot, containing ≈55 mg insulin/g of fibers, has been characterized in vitro by investigation of the desorption kinetics of the insulin from the fibrous depot. It has been shown that insulin is controllably released in quantities of 1.3-1.6 mg of insulin during 24 hours, in the course of 20 days. The results of biocompatibility tests have shown that the examined artificial depot neither shows irritating effects nor provokes sensitizing or cytotoxic effects. Therefore, these materials are acceptable for use in a direct contact with tissue of a living organism.