Selenium concentrations in liver, hair, feces, and blood of Kesterson raccoons exceeded Volta concentrations by 12, 30, 21 and 10 times, respectively. Selenium concentrations in hair provided the strongest statistical separation between areas. Selenium concentrations in livers of Kesterson raccoons were less than those found in five of nine other species of mammals sampled in 1984. Hence, the raccoon did not appear unusual in its accumulation of selenium. Based on our sample of 12 raccoons, we found no evidence that contamination by irrigation drainwater had negative effects on the raccoon population at Kesterson.