Abstract: Objective To understand the prevalence of drug resistant tuberculosis (TB) and related risk factors in floating population in Ningbo, and provide evidence for the prevention and control of TB. Methods All the sputum culture positive TB patients in floating population were recruited as study subjects during the drug resistant TB surveillance in Ningbo from 2007 to 2010. The identification of culture positive strains and drug susceptibility test of these strains to isoniazid, rifampicin, streptomycin and ethambutol were conducted. Univariate and multivariate analysis were performed on the drug resistance related factors. Results Among 562 TB patients recruited in the study, 501 were infected with Mycobacterium tuberculosis complex (89.1%) and 61 were infected with Mycobacterium non-tuberculosis. The total drug resistant rate was 31.9% (160/501), the total multi-drug resistant (MDR) rate was 6.9% (35/501). The initial drug resistant rate was 28.0% (124/442), and the initial MDR rate was 4.8% (21/442). The acquired drug resistant rate was 61.0% (36/59) and the acquired MDR rate was 23.7% (14/59). The history of previous TB treatment was significantly associated with TB drug resistance. Conclusion The prevalence of drug resistant TB in floating population was high in Ningbo, suggesting the necessity to strengthen the TB control in floating population.