Three decades ago, planned obsolescence was a widely discussed ethical issue in marketing classrooms. Planned obsolescence is topical again today because an increasing emphasis on continuous product development promotes shorter durables replacement and disposal cycles with troublesome environmental consequences. This paper offers explanations of why product obsolescence is practiced and why it works. It then examines the ethical responsibilities of product developers and corporate strategists and their differing responses to this problem. Pro-environment product design and marketing practices and innovative government policies may alleviate the problem over time. However, given the current lack of understanding about consumer replacement and disposal behavior, it is questionable as to whether these practices and policies will be sufficiently informed to be effective. Thus, marketing scholars have a significant opportunity to contribute to sustainable durables product development.