Although state-sponsored human rights abuses have long been commonplace, the psychological profiles of perpetrators are not well delineated. This article examines the utility of the diagnosis of sadistic personality disorder (SPD) in explaining the commission of atrocities. The history of, and controversies surrounding, SPD are briefly reviewed. Using a case study from the amnesty trials of the Truth and Reconciliation Commission (TRC) in South Africa, the relevance of the SPD diagnosis for an infamous perpetrator of political violence is debated. Sources of data include the perpetrator's autobiography, transcripts from the amnesty trial, and Structured Clinical Interview for DSM-IV Axis II Personality Disorders (SCID-II; First, Spitzer, Gibbon, & Williams, 1994) ratings provided by four people who had contact with the perpetrator during his trial. The authors provide arguments for and against the use of the SPD diagnosis in this case and in similar contexts of perpetration. It is proposed that neither psychological reductionism nor social reductionism can adequately account for the motivations of political perpetrators, and an integrative approach to the understanding of perpetrators is advocated. Implications for diagnostic criteria are discussed.