In an unselected sample of 45 subjects who received out-patient enuresis treatment data were collected with semi-structured interviews and other measures to examine conditions of successful participation in therapy. Subjects were assigned to three groups, first those who completed the course of therapy, second those who dropped out of therapy, and third those who didn't start with therapy after the initial interview. Results show that initially assessed variables like subjective suffering, capability and readiness to cooperate differentiate best between the groups. It was concluded that the manner of cooperating is a most significant factor in successful therapies and that therefore it is necessary to assess the individual manner of cooperating before applying standardized therapeutic procedures.