Drawing on the theoretical foundation of obsessive-compulsive spectrum disorder, this article develops an expanded conceptualization and new measure of consumers' proclivity to buy compulsively. Compulsive buying is defined as a consumer's tendency to be preoccupied with buying that is revealed through repetitive buying and a lack of impulse control over buying. This measure includes dimensions of both obsessive-compulsive and impulse-control disorders. By measuring income-dependent items or consequences of compulsive buying separately from the compulsive-buying scale, we develop a measure that has a strong theoretical foundation, well-documented psychometric properties, and an ability to be applied to general consumer populations. (c) 2008 by JOURNAL OF CONSUMER RESEARCH, Inc..