Corn demand for ethanol production is rapidly increasing and it will become critical to maximize grain quality for ethanol production. The objective of this study was to analyze the effects of the major management practices and their interaction with genetics and location on the grain and ethanol yield (L/Mg grain) of corn hybrids. The experiment was conducted at three locations in IL. In each of these locations the management practices evaluated were nitrogen (N) fertilization (0 to 280 kg N/ha) and plant population (70 to 100 thousand plants/ha), whereas previous crop (corn and soybean) was also evaluated in one site. The same four hybrids were planted at all locations and in one site eight additional hybrids were evaluated. Mean ethanol yield ranged from 428 to 447 L/Mg whereas grain yield ranged from 9.9 to 13.8 Mg/ha for the 12 hybrids evaluated in this site. Nitrogen fertilization decreased ethanol yield (averaged across locations from 438 without N to 431 L/Mg with 280 kg N/ha) and increased grain yield at all locations (averaged across locations from 9.8 to 13.8 Mg/ha) and for all hybrids, although there was a significant interaction between N and the other factors. The effect of plant population was significant and positive for ethanol yield at all locations but of smaller magnitude than that of nitrogen (averaged across locations from 430 to 434 for 70 and 100 thousand plants/ha, respectively). Plant population affected grain yield in two locations. Ethanol yield was higher and grain yield was lower for corn than soybean as previous crop but this difference was more pronounced at intermediate nitrogen rates and disappeared at the highest two nitrogen rates.