Inulinase is an enzyme catalyzing the hydrolysis of inulin, a plant reserve polysaccharide, into fructoses and fructo-oligosaccharides which are widely used in pharmaceutical and food industry. Although several substrates for the production of inulinase have been reported as being economically effective such as utilization of inulin-rich substrate rather than pure inulin, however, there is still need to develop the substrate to make the entire process much cheaper and more effective. Here we reported inulinase production from Acinetobacter as there is not found any report on inulinase production from Acinetobacter. Eight isolates of Acinetobacter baumannii were isolated from different agricultural rhizosphere soil samples and screened for higher inulinase production, Acinetobacter baumanniiRs5 gave higher inhibition zone around the colony in comparison with other isolates. The enzyme activity was increased to 3.97 U/ml when this isolate was cultivated under the optimal conditions which consisted of using basal medium containing 4%(w/v) inulin extract from dahlia tubercles and 2%(w/v) treptone at pH7. 5 at 28 C for 22 hour. The enzyme revealed maximum activity (4.32 U/ml) in the presence of dahlia tubercles (2% w/v) followed by garlic with activity of 4.09 U/ml as substrates. Consequently, dahlia has a potential as an effective and much cheaper (economical) substrate for inulinase production and inulinase activity in comparison with traditionally used substrates like pure inulin and other saccharides.