Aims:  To access inulinase production by Xanthomonas campestris pv phaseoli using the submerged and solid state cultivation (SSC) methods. Methods and Results:  Various carbon sources, inulin‐rich solid substrates and pure synthetic inulin were tested for their efficiency in inulinase induction. The highest inulinase production (17·42 IU ml−1) in submerged cultures of X. campestris was observed with inulin as a carbon source with an initial pH, temperature and agitation of 7·0, 37°C and 150 rev min−1 respectively. Among the various substrates, garlic peels (117 IU gds−1) and onion peels (101 IU gds−1) were found to be the best for inulinase production. Conclusion:  The inulinase production level of X. campestris was 6·7‐fold higher in garlic and 5·8‐fold in onion, under optimized SSC conditions compared with the submerged culture. Significance and Impact of the Study:  This is the first report on inulinase production from garlic and onion peels by X. campestris using SSC. SSC is an efficient method for inulinase production by X. campestris for commercial applications.