© 2018, Pleiades Publishing, Inc. The degradation of native and pretreated nitrocellulose (NC) by the microscopic fungus Fusarium solani VKM F-819 and a mixed culture of the fungus with a sulfate-reducing bacterium Desulfovibrio desulfuricans VKM B-1388 has been studied. It has been shown that NC pretreatment with UV radiation and ozone promoted its subsequent biodegradation. The degradation of the thus treated NC by a mixed culture of F. solani and D. desulfuricans was the most effective as compared to all other treatment options. The NC nitrogen content decreased from 13.38 to 10.03%; the number average (Mn) and weight average (Mw) molecular masses decreased by three and two times, respectively. These magnitudes were achieved after 5 days of incubation of the pretreated NC. The obtained data can be used to further develop NC degradation technology.