The current study tested hypotheses derived from Joiner's (2005) interpersonal theory of suicide, which proposes that deliberate self-harm (DSH) becomes increasingly more reinforcing with repetition. One hundred six participants with a history of DSH completed questionnaires about their emotions and experience of physical pain during their most recent DSH episode. Consistent with prediction, people with more numerous past DSH episodes felt more soothed, more relieved, and calmer following their most recent episode of DSH. Contrary to prediction, greater numbers of past DSH episodes were associated with more intense physical pain during the most recent episode. The findings suggest that the emotion regulation functions of DSH may become more reinforcing with repetition.