The degradation of [carbonyl‐14C] ‐ cis, trans‐permethrin was studied in Dubbs fine sandy loam soil incubated at 10, 25, and 40°C from 0 to 64 days. The most rapid degradation of permethrin to [carbonyl‐14C] ‐cis,‐trans‐3‐ (2,2‐dichloroethenyl)‐2,2‐dimethylcyclopropanecarboxylic acid (DCVA) and ultimately14CO2occurred at 25°C. Rapid degradation to DCVA also occurred at 40°C, however, further degradation of DCVA to14CO2was reduced. Permethrin degradation to14CO2was slowest at 10°C. The de gradation rate oftrans‐permethrin was greater than thecis‐permethrin at all temperatures tested. The halflives ofcis‐andtrans‐permethrin were 55 and 14 days at 10°C, 12 and 5 days at 25°C, and 27 and 4 days at 40°C, respectively. Compounds identified from treated soil were the original [carbonyl‐14C] ‐cis,trans‐permethrin and the major degradation products cis‐, andtrans‐DCVA.