Although the development and survival of Diabrotica virgifera virgifera LeConte have been studied under various conditions in field corn, there is not a clear understanding of stage specific mortality. There is also a need to understand how western corn rootworm development may be affected by new management technologies such as rootworm-protected transgenic corn. Therefore, the objective of this study was to use a life table approach to compare stage specific mortality of western corn rootworm reared on Monsanto event MON 863 vs. a non-transgenic isoline in the field. The study was conducted during 2004 and 2005 at the University of Nebraska Agricultural Research and Development Center, near Mead, NE in an area planted to soybean the previous year. A randomized complete block design was used with two treatments (MON 863 transgenic hybrid, non-transgenic isoline hybrid) and five replications. Western corn rootworm eggs were artificially infested with a tractor-mounted pressurized applicator to establish live egg cohorts of known size in each row per treatment. Each year, established sampling and sample processing techniques were used twice a week over a two month period to recover and identify immature rootworm life stages from egg through adult periods. Life stage data from reps were analyzed to determine possible treatment x time interactions with life stage or stage specific mortality. Stage specific mortality varied significantly among life stages and among treatments over time. Results will be discussed within the context of our current understanding of the species biology and insect resistance management.