Maximum profit is an appropriate criterion for the selection of the optimum machining conditions rather than the conventional criteria of minimum cost or maximum production rate. A simple example is presented to illustrate the determination of the maximum-profit cutting speed by application of a fundamental economic principle that maximum profit occurs at the production rate where the marginal revenue equals the marginal cost. The effects of the demand function, feed, and cost and time parameters on the determination of the maximum-profit cutting speed are analyzed. Emphasis is given to the investigation of a range of optimum cutting speeds, instead of the theoretical optimum speed, for practical applications.