Before the invention of a combine harvester, corn was picked on the ear and threshed later. This led to an availability of corn cobs and many uses were found. A renewed interest in the heat/energy value of the cob has increased the focus on harvesting corn cobs. A corn cob separation system was developed and installed on a single pass biomass harvesting combine. The system included a blower and two fans and the combine was capable of harvesting grain only, grain and stover, and grain and cobs. The cob separation system was evaluated using a stationary test with earcorn and stover bales with minimal field testing to validate the lab tests. The stationary tests evaluated 5 different separation zone configurations, 2 blower speeds, and 2 fan speeds. Cob purity averaged 71% and the collection efficiency averaged 84% with fan power consumption of 20 and 36 kW and blower power consumption of 3.1 and 5.3 kW. Field tests showed cob purity averages of 84% while the collection efficiency averaged 76%.