Aims This study evaluates flonicamid biotransformation ability of Aminobacter sp. CGMCC 1.17253 and the enzyme catalytic mechanism involved. Methods and Results Flonicamid transformed by resting cells of Aminobacter sp. CGMCC 1.17253 was carried out. Aminobacter sp. CGMCC 1.17253 converts flonicamid into N‐(4‐trifluoromethylnicotinoyl) glycinamide (TFNG‐AM). Aminobacter sp. CGMCC 1.17253 transforms 31·1% of the flonicamid in a 200 mg l−1 conversion solution in 96 h. Aminobacter sp. CGMCC 1.17253 was inoculated in soil, and 72·1% of flonicamid with a concentration of 0·21 μmol g−1 was transformed in 9 days. The recombinant Escherichia coli expressing Aminobacter sp. CGMCC 1.17253 nitrile hydratase (NHase) and purified NHase were tested for the flonicamid transformation ability, both of them acquired the ability to transform flonicamid into TFNG‐AM. Conclusions Aminobacter sp. CGMCC 1.17253 transforms flonicamid into TFNG‐AM via hydration pathway mediated by cobalt‐containing NHase. Significance and Impact of the Study This is the first report that bacteria of genus Aminobacter has flonicamid‐transforming ability. This study enhances our understanding of flonicamid‐degrading mechanism. Aminobacter sp. CGMCC 1.17253 has the potential for bioremediation of flonicamid pollution.