Field studies were conducted in 1989 and 1990 to determine if corn seed treated with naphthalic anhydride (NA) at 0.5% (w/w) would result in a reduction in corn injury caused by clomazone applied preplant incorporated (PPI) or preemergence (PRE) at 0.56 and 0.70 kg a.i. ha–1. NA significantly reduced corn injury, especially where clomazone was incorporated. Plant population, height, ear number, and grain yield also were higher in plots where NA was used. In most instances, corn injury was less and plant population, height, ear number, and grain yield were higher in plots where clomazone was applied PRE compared with PPI.