Aerial seeding of Italian annual ryegrass (Lolium multiflorum) is a common, but controversial, emergency rehabilitation practice following wildfire in California. Replicated study plots, with and without ryegrass, established after a summertime chaparral wildfire on California's central coast revealed the following: 1. Ryegrass-seeded plots developed significantly greater total plant cover than unseeded plots in the first year. 2. Regeneration and growth of native species were significantly depressed in the presence of ryegrass. 3. Soil erosion was significantly greater on ryegrass-seeded plots than on unseeded plots. 4. Pocket gopher activity was greater on ryegrass-seeded plots than on unseeded plots. These results suggest that ryegrass seeding for emergency rehabilitation of burned areas can be ineffective, and even counterproductive, in certain cases.