Excess nutrients in runoff from soils amended with dairy-manure sludge (DMS) can contribute to water-quality degradation. Most of the dairy farms in Puerto Rico have overhead irrigation systems in which pasture fields receive DMS from retention lagoons following USDA-NRCS code 590 specifications. Nutrient and sediment losses were quantified from DMS amended pasture fields at levels ranging from of 41 to 68 kg N/ha and 14 to 23 kg P/ha in an Oxisol and an Ultisol having “medium” and “high” soil test phosphorus (STP) levels of two dairy farms in Puerto Rico. Concentrations of dissolved phosphorus (DP), total phosphorus (TP) and NO3-N at 30 minutes of runoff after simulated rainfall of 70 mm/hr were repeatedly quantified 1, 7, 14 and 21 days, following DMS application. Unamended soils within the range of soil test levels evaluated, have P concentrations in runoff that are below suggested environmental threshold limits. Soils with “high” STP levels had higher runoff DP and TP concentrations than soils with “medium” STP levels 1-day following DMS ammendment. Phosphorus-sorption saturation phenomena may explain that, at equal levels of DMS amendment runoff DP and TP concentrations decreased with time in soils having “high” STP, yet concentrations were similar at all time periods in soils having “medium” STP. The differences of P concentrations in runoff were greater between amended and unamended soils with “high” STP levels, than in soils with “medium” STP levels. Nitrate concentrations in runoff were greatly influenced by DMS application, STP level and time after application. Runoff P concentrations from these tropical soils are influenced more by the DMS amendment when the soils test “high” than in when soils test “medium” in STP.