Technical Abstract: The percent of viable eggs of the western corn rootworm, Diabrotica virgifera virgifera LeConte, which survived to the adult stage was evaluated for the effect of egg density in 2005 and 2007 in Central Missouri. In 2005, each plot was 2.44 m × 3.05 m and contained 64 maize, Zea mays L., plants. In 2007, plots were 3.05 m × 3.05 m and again contained 64 maize plants. Seven egg densities (25, 50, 100, 300, 600, 1200, and 2400 viable eggs per 30.5 cm) were evaluated with 6, 5, 5, 4, 4, 4, and 4 replications, respectively, in each year in a completely randomized design. In 2007 only, an additional row was infested near each plot to evaluate plant damage. In both years, there was no correlation of infestation level and percent emergence between infestation levels of 25 to 600 viable eggs per 30.5 cm. In 2005, 8.6% of the viable eggs established on a corn plant and produced an adult at these lower infestation rates. In 2007, this value was 2.9%. Regardless of egg density, at least 91 to 97% failed to establish and produce adults (density-independent mortality). In 2005 and in the combined analysis, as viable egg densities increased from 600 to 2400 per 30.5 cm there was a significant decrease in percent emergence. In a broken line analysis, the point where density-dependent mortality began in the combined analysis was 881 eggs per 30.5 cm with a 95% confidence interval from 675 to 1088. In 2005, density-dependent mortality was important at high infestations and killed 58% of those larvae that successfully established on a plant at the highest egg density. However, little or no density-dependent mortality occurred at infestation levels less than 850 viable eggs per 30.5 cm in either year of the study. These data are discussed in terms of dose calculations for products targeting the western corn rootworm.