We examined the effect of soil salinity on the degradation of chlorpyrifos and the residual effect of chlorpyrifos and its metabolites on soil P fractionation during 60-day aerobic incubation. A sandy loam soil (Typic Psammaquents) was collected from the Daeho reclaimed tideland and two-thirds of the soil was applied with Na salt to get three different soil salinity levels: 4.6 (low, EL), 9.7 (medium, EM), and 14.4 (high, EH) dS m -1 . Estimated half-lives for chlorpyrifos degradation were 7.1 in EL, 10.0 in EM and 16.9 days in EH soils. During the degradation of chlorpyrifos in soil, microbial activity decreased by increasing soil salinity and its inhibitory effect increased with time. In contrast, the addition of chlorpyrifos did not inhibit soil alkaline phosphatase (SAP) activity, which was higher in EH than in control soils. Chlorpyrifos added at a rate of 5.0 mg a.i. kg -1 dry soil did not affect the distribution pattern of P fractions in control soils. Both an increase in soil salinity and soil sterilization increased the Ca-bound P fraction and decreased the occluded Fe + Al-bound P fraction with a significant interaction between soil salinity and sterilization. With time, the Ca-bound P fraction increased and organic-and occluded Fe + Al-bound P fractions decreased, while total-P, available-P, and non-occluded + adsorbed P fraction remained unchanged. Particularly, organic-P was mineralized more in EH than in control soils and the Ca-bound P fraction contained the highest inorganic P released. Mineralization of organic P and partitioning of released P in the recalcitrant Ca-bound P fraction increased by increasing soil salinity, while available P fraction remained unchanged, suggesting that the addition of chlorpyrifos at the currently recommended dosage level did not seem to considerably affect the available P fraction with low P leaching potential to waterways.