The focus of this research work was to investigate the microbial bioavailability of the herbicide [¹⁴C] Metolachlor in Illinois soils like Flanagan, Catlin and Drummer incubated under anaerobic and aerobic soil environmental conditions. All of these soils exhibited a lag period before starting a significant mineralization of the herbicide which could be attributed to the microbial acclimation phase.  Anaerobiosis induced more mineralization and greater dissipation of the herbicide from the soils. Also significant amount of the herbicide was persisted as bound residue in both soil environments and become immune to the microbial attack. The nitrate and ferrous flux in these soils during the degradation of [¹⁴C] Metolachlor was also monitored throughout the experiment.  The observations from the present study may be utilized for perceiving the role of limiting nutrient in the microbial degradation of [¹⁴C] Metolachlor, which in turn may be used for framing a bio-stimulation (addition of nutrient or electron acceptors to stimulate the indigenous microorganism) strategy for the rapid cleanup of the herbicide from the contaminated soils.