Abstract: Rhizoctonia solani isolated from Tekirdag-Turkey soil, was found to produce a very active inulinase enzyme. The optimum conditions for enzyme production were determined. Maximum growth was observed at 45°C while the highest inulinase production was determined at 40°C. The best inulinase production was observed at an initial medium pH 6.0 and on the first day of cultivation time. Inulin and Jerusalem artichoke powder as carbon source were the most effective on production of inulinase from R. solani. The highest productivity was recorded in the presence of 10 mM NH4H2PO4+10 mM NH4NO3 as nitrogen source.