The purpose of this study was to determine effect of temperature on bioremediation of a diesel fuel contaminated heavy clay soil under simulated landfarming conditions. The Arrhenius temperature coefficient, $\theta,$ was determined to quantify the effect of temperature on biodegradation rate. Biodegradation was measured in soil microcosms by monitoring headspace oxygen concentration and $\sp{14}$CO$\sb2$ evolution from the mineralization of $\sp{14}$C-octadecane. Zero-order biodegradation rates, calculated from oxygen consumption on a tetradecane (n-C$\sb{14})$ equivalent basis, were found to range from 0.13 mg $\rm kg\sp{-1}day\sp{-1}$ at 3$\sp\circ$C to 9.8 mg $\rm kg\sp{-1}day\sp{-1}$ at 22$\sp\circ$C (on a dry weight basis). The average temperature coefficient was 1.19 for the biodegradation rates based on oxygen consumption and 1.11 for the biodegradation rates based on $\sp{14}$CO$\sb2$ evolution. The diesel range n-alkanes remaining in the soil (active and abiotic samples) at the end of the experiment were analyzed by gas chromatography (GC/FID) and compared to fresh unweathered standards to determine the effect of temperature on the final hydrocarbon depletion. The direct measurement of total extractable hydrocarbons at the end of the experiment was not possible since the integration program was not set up to only integrate the n-alkane peaks. (Abstract shortened by UMI.)