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. This is now the third year of this study, and yield results from row spacings narrower than 30 inches 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. Interest in this new concept, twin row corn, has prompted many new 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-inch spacing. Another potential set of advantages is better seed placement, more accurate plant spacing, and greater sunlight utilization.