Adoption of variable-rate N management by North American corn (Zea mays L.) producers is low, despite the potential economic and environmental benefits of this practice. A major obstacle is that recommended N fertilizer rates based on yield goal are often poorly correlated with actual economically optimum N rates. Nitrogen response patterns are often field- and season-specific and can vary widely within the same field, further complicating adoption. Side-by-side comparisons of uniform- and variable-rate N management have revealed no consistent advantages for either strategy in yields achieved, profitability, whole-field N usage, or N-use efficiency by plants. In the future, a better understanding of temporal variation in N soil test levels, better crop simulation models, and improved N sensing and application equipment may assist growers in capturing the benefits of site-specific N management.