The objective of this research was to investigate the dissipation of the herbicide dimethenamid under anaerobic redox conditions that may develop in the soil environment. Soil-water biometers were prepared with a saturated soil and made anaerobic by either glucose pretreatment (according to the Environmental Protection Agency registration study for anaerobic fate) or N2 sparging. Treatments included glucose pretreatment, NO3- + SO42- amendment, unamended, and autoclaved. Volatile, aqueous, extractable, and bound (unextractable) 14C-residues were quantified and characterized. The redox potential decreased over time, and evidence of denitrifying, iron-reducing, sulfate-reducing, and methanogenic conditions was observed, depending on the amendments. Anaerobic degradation of 14C-dimethenamid occurred in all treatments, and the time observed for 50% disappearance (DT50) was 13-14 days for nonautoclaved treatments. 14C-metabolites accumulated to up to 20% of applied 14C. At least two major metabolites were observed in nonautoclaved treatments, whereas only one was observed in autoclaved microcosms. More than 50% of the applied 14C was eventually incorporated into soil-bound residue.