This study was carried out to investigate the adsorption and the degradation of herbicide napropamide in soils tinder laboratory conditions. The adsorption distribution coefficients(Kd) of napropamide in 3 soils varied from 5.38 to 11.39. With higher content of organic matter in soils, the extent of adsorption was high. The rapid degradation of napropamide took place after a lag period. The time to 50% loss of napropamide was approximately 65, 45 and 30 days in soil incubated at 10, 20 and $30^{circ}C$, respectively. The time to the 90% loss varied from about 90 days at $10^{circ}C$ to about 45 days at $30^{circ}C$. In the soil pre-incubated with napropamide, the herbicide degraded without a lag time, and the rate of degradation was also accelerated. This should be a evidence on enhanced biodegradation of napropamide in soil with the repeat-application.