In recent years, growers have expressed renewed interest in producing corn in row spacings narrower than 30 inches. Research to compare corn yields with various row spacings has either been done with a cornhead matched to the row spacing or with hand harvesting. Some commercial producers using narrow rows have used a 30-in. cornhead at a slower speed and have ignored field losses. The objective of this study was to determine if visible machine harvest losses differed between narrow and wide cornheads and to determine the extent of harvest loss when 15- in. rows are harvested by a 30-in. row cornhead.