The continuing debate over the deeply controversial issue of physician-assisted suicide has been complicated by confusion about how this practice resembles or differs from refusal of life-sustaining treatment. Perspectives on ethics and policy hinge on the contested issue of whether a valid distinction can be made between assisted suicide and withdrawal of treatment. This paper uses three illustrative cases to examine leading arguments for and against the recognition of a fundamental distinction between these practices. The first case involves assisted suicide by ingestion of prescribed barbiturates, the second involves withdrawal of artificial nutrition and hydration, and the third involves a decision to stop eating and drinking. On theoretical and practical grounds, this paper defends the position that there is a valid distinction between assisted suicide and refusal of treatment.