Volatilization of diesel oil in sand columns was conducted at the ambient temperature of 20 °C by spilling oil on the sand surface. The weight loss of oil was determined by pre and post weight of the sand columns and desiccant was measured on an electronic balance. The aim of this paper was to investigate the effect of moisture content on the volatilization of diesel oil in sand. The results show that the diesel oil and water in sand both volatilize at a linear rate with respect to time. The largest volatilization mass of diesel oil and water reach when the moisture contents are 8% and 20% respectively. Appropriate water content can help to pull the oil contaminants to the surface of the sand.