Technical Abstract: Soil organic matter is an important factor affecting the fate of fumigants and organic amendment of surface soils could reduce fumigant emissions by accelerating fumigant degradation and increasing adsorption. Experiments were conducted to determine the degradation rate of cis- and trans-1,3-dichloropropene (1,3-D) and chloropicrin (CP) in soils with organic amendment under a range of soil moisture, temperature, sterilization, and soil texture conditions. Degradation of the fumigants followed availability-adjusted first-order or pseudo first-order kinetics with slower degradation of 1,3-D than CP. Increasing soil water content from 5% to 17.5% (w/w) slightly increased the degradation of 1,3-D, but not CP. All five organic amendments at 5% (w/w) increased fumigant degradation 1.4-6.3 fold. The degradation of both fumigants was accelerated with increasing amount of organic material (OM). Little interaction between soil moisture and OM was observed. Autoclaved soils did not reduce degradation of either fumigant. Increased temperature from 10 to 45 ºC accelerated fumigant degradation 5-14 times. Soil texture did not affect 1,3-D degradation but CP degraded faster in finer-textured soil. These results suggest that OM type and rate and soil temperature are the most important factors affecting degradation of 1,3-D and CP.