Compost amendment to agricultural soils has been shown to either reduce disease incidence, conserve soil moisture, control weeds or improve soil fertility. Application of compost can range from 5 to 250 Mt·ha–1 (N content up to 4%). Large application of compost with high N and P levels may result in excessive leaching of nitrate, ammonium, and phosphate into groundwater. It could be a serious concern on the east coast of Florida with its high annual rainfall and shallow water table. In this study, five composts (sugarcane filtercake, biosolids, and mixtures of municipal solid wastes and biosolids) were collected from different facilities throughout Florida. Composts were applied on a surface of 15-cm sandy soil columns at the rate of 100 Mt·ha–1 on the surface basis and leached with deionized water by 300 ml·d–1 for 5 days (equivalent to 34 cm rainfall). The concentrations of NO3-N, NH4-N, and PO4-P in leachates reached as high as 246, 29, and 142 mg·L–1, respectively. The amount of N and P leached following 5-day leaching events accounted for 3.3% to 15.8% of total N and 0.2% to 2.8% of total P as inorganic forms.