Compost use in landscaping and erosion control applications has become widespread. Various types of composts have been utilized on highway embankments. Erosion resistance could vary with different compost materials. The objective of this study is to investigate the erosion resistance of three types of widely used composts. Rainfall simulators were constructed to simulate natural rain of 3.0 in/hr. Soil boxes were designed and built to simulate inclined embankments. Bench scale experiments were first conducted to test the erosion of natural base soils (sand, silt, and sandy clay) under 1 hr rainfall. Excessive soil losses were observed in all base soils, and silt slope failed during the test. Then repeated rainfall erosion tests were performed on sandy slopes with three types of composts covers (green compost, manure compost, and biosolid and green material co-composts). The co-compost slope retained stability and the other two compost slopes failed. Chemical and biological constituents in the runoff were analyzed. The concentrations of the analyzed constituents were high in the initial rainfall event and reduced with sequential rainfalls. Most of the toxic metal concentrations in the runoff were less than the EPA criteria. Copyright ASCE 2008.