Recent studies have indicated that wetlands may serve as a source of phosphorus rather than a sink.  Understanding the mechanisms and factors controlling P sorption in wetland environments is necessary to evaluate the P removal capacities of both natural and created wetlands.  This study compares the chemical composition, P release, and P sorption potential of two commercial composts to that of two organic wetland soils.  Commercial composts had significantly higher levels of Total P as compared to the organic wetland soils. Total P levels were 2454 mg kg^-1 and 2410 mg kg^-1 for the Leaf Compost and the Lobster Compost, respectively. Commercial composts had significantly higher levels of Morgan's extractable P levels as compared to the organic wetland soils. Extractable P levels were 131 mg kg^-1 and 90 mg kg^-1 for the Leaf Compost and Lobster Compost, respectively. P release was measured under aerobic, anaerobic, and saturated conditions. Under all redox conditions, the commercially available composts had significantly higher levels of SRP as compared to the organic wetland soils. For all samples, the release of SRP increased with the duration of the saturation period. P sorption was fitted to Langmuir for all samples except the anaerobic leaf compost. P sorption maxima under aerobic conditions were 2902 mg kg^-1, 1811 mg kg^-1, 823 mg kg^-1, and 625 mg kg^-1 for the peat, muck, Lobster Compost, and Leaf Compost, respectively.  P sorption maxima under anaerobic conditions were 1788 mg kg^-1, 1353 mg kg^-1, and 2125 mg kg^-1, for the peat, muck, and Lobster Compost, respectively.  Study results suggest that composts should be carefully examined prior to their utilization as organic amendments in created wetlands as certain composts may contribute to higher levels of SRP release than natural organic wetland soils.