The bacterium Serratia marsescens strain JAS16 was isolated from agricultural soil which had prior exposure to monocrotophos for three years. The strain JAS16 tolerated up to 1200 mg L–1 monocrotophos and degraded the insecticide (1000 mg L–1) at a degradation rate constant of 136 d−1 (DT50 = 3.7 d). In soil, the degradation rate constant was 105 d−1 (DT50 = 4.8 d). A schematic pathway is being proposed from the degraded products derived from gas chromatography--mass spectrometry (GC-MS). The phytotoxicity of degradation products to Vigna radiata, Vigna unguiculata, and Macrotyloma uniflorum and the genotoxicity to Allium cepa roots were found to be low. A cost-effective powder-based formulation was achieved with the isolate. The isolate remained viable during the storage and also multiplied with a higher colony forming units (CFU) load g–1 for over a period of seven weeks of storage. © 2015 Taylor & Francis.