From 1976 through 1979 blueberry (Vaccinium corymbosum, cv. Bluecrop) plots received five rates of ammonium sulfate [(NH4)2SO4] supplying 28, 84, 140, 196 and 252 kg nitrogen (N)/hectare/ year. Response was measured by fruit yield and mineral element analysis of leaves and soil. The highest average yield was produced from plots receiving 140 kg N/hectare, from plants with a leaf N of 1.96 to 2.06 percent dry weight, and from soil with a pH of about 4.6.