The TopCross grain production system is rapidly gaining popularity as the preferred method of producing high‐oil corn (Zea mays L.). A blend (TC Blend) of two types of corn is planted to produce TopCross high‐oil corn (HOC) grain. Limited information is available on the effects of the TopCross system on agronomic traits that may determine the profitability of HOC production. Field experiments and on‐farm studies were performed in 1995 to 1999 across a range of production environments in Ohio to compare the agronomic performance of TC Blends with their conventional counterparts (check hybrids). Grain yields of TC Blends averaged across experiments and on‐farm studies were 8% less than those of check hybrids. The TC Blends were as tolerant to drought conditions as the check hybrids. Stalk lodging and barrenness were comparable for TC Blends and check hybrids. Little evidence existed that kernel set in TC Blends was reduced by inadequate pollen availability due to the limited number of pollinator plants in the blend. Factors that may contribute to the differences in grain yields between TC Blends and check hybrids included lower plant populations in TC Blends at harvest, competition between the two components of the blend (TC Blend pollinators and male sterile grain parents), and the physiological cost of oil synthesis. The lower grain yield, higher grain moisture content, and lower test weight associated with TC Blends should be considered when determining TopCross HOC production costs, especially if HOC grain is being produced under contract.