During the 1960's, a number of watersheds located in the San Dimas Experimental Forest (SDEF) in southern California were type-converted from native chaparral to grassland. In 2002, the Williams Fire burned >90% of the SDEF, providing an opportunity to investigate differences in soil water repellency and hydrologic response between grass converted and native chaparral watersheds. Soil moisture and water repellency were sampled winter and summer for 4-years. Peak flows were measured in six 1-3 ha watersheds using trapezoidal flumes with automated stage-height recorders. Sediment yields were measured by making repeated sag-tape surveys of the wedges of material accumulating in small debris basins located at the bottom of each watershed. At the 2 cm depth, water repellency approached 40% in the grass watersheds, suggesting that repellency was influenced by the rapid fine root turnover of perennial veldt grass (Ehrharta calycina). At the soil surface, post-fire repellency decreased dramatically during the first winter rain events, and remained low over the 4-years following the wildfire. At soil moisture contents greater than 10%, the occurrence of soil water repellency was reduced to below 10% at all depths, implying that infiltration was not impaired. Post-fire peak flows ranged from 0.1 to > 0.4 m3s-1ha-1. Peak discharge was large during the first post-fire winter, despite only moderate rainfall amounts and intensities, and again during the record storms of 2005. There was little difference in peak flow with the two vegetation types over the period of study. Annual sediment yield was as high as 38 m3 ha-1. Most of the sediment was produced during the initial post-fire winter, with the chaparral watersheds generating slightly more sediment than the grass. Sediment yield was negligible in subsequent years after the fire, despite the record rains.