Correctional mental health clinicians are sometimes asked to assess disciplinary responsibility, that is, to ascertain whether an inmate is culpable for violating prison rules. This assessment of disciplinary responsibility is akin to insanity determinations in criminal proceedings. In this article, I review the moral, legal, and practical aspects of disciplinary responsibility. I use California's test of responsibility for prison misconduct, which is similar to the Durham rule, to illustrate some of the dilemmas involved in creating and implementing a test of disciplinary responsibility.