Nitrogen management has traditionally focused on evaluating crop N requirements using N response functions coupled with plant and soil testing to diagnose N deficiencies and fertilizer needs. Estimated N use efficiencies are implicit in many of these approaches, but measures of inefficient N use, including surplus N and N losses, are often not explicitly utilized in N management programs. Excess N can be defined as available soil N that exceeds current crop requirements and has a high risk of loss to environmentally adverse pathways during the course of a crop sequence or rotation. Assessment of N surpluses and losses has been the focus of many recent studies through measures of soil properties (e.g. residual nitrate, pre-sidedress nitrate), crop characteristics (e.g. stalk nitrate, petiole nitrate), and crop performance (e.g. N recovery, N inputs versus outputs). Our objectives are to review current methods of assessing excess N in cropping systems and to explore their application in evaluating N management practices and in formulating revised N recommendations. Developing methods to identify and evaluate practices or conditions contributing to excess N will be an increasingly important part of N management as adverse environmental and economic impacts of surplus N increase.