An operationalization of mental pain is presented in three studies. The first study describes the operationalization of mental pain and the factor structure of the items produced by a content analysis of self-reports yielding a scale with nine factors: the experience of irreversibility, loss of control, narcissistic wounds, emotional flooding, freezing, estrangement, confusion, social distancing, and emptiness. Study 2 tested the relationship between mental pain and depression and anxiety in a normal population. Study 3 focused on the relationship between mental pain and coping. Mental pain is conceptualized as a perception of negative changes in the self and its functions that are accompanied by negative feelings. It is suggested that it can be meaningfully applied to the study of different mental states, life conditions, and transitions in life.