Interest in narrow-row corn and, more recently, twin-row corn has increased over the last several years. Research done in the 1990s in various locations throughout the Corn Belt has demonstrated significant yield advantages of narrowing corn rows from 38 in. to 30 in., and yield results from row spacings narrower than 30 in. have indicated a greater likelihood of a yield response in the northern part of the Corn Belt. Yield increases for narrow row spacing in corn from the central to southern areas of the Corn Belt have been inconsistent. This new concept of twin-row corn has prompted many questions about row spacing in corn. One of the advantages of twin-row corn is that no major modifications of harvest or spray equipment are necessary when converting from single-row 30-in. spacing. Other potential advantages are better seed placement, more accurate plant spacing, and greater sunlight utilization. This is the fourth year we have done this study.