The most common reasons given by patients for dropping out of treatment are: environmental constraints, dissatisfaction with services and that they no longer need help. In this study two groups of patients suffering from obsessive-compulsive disorders are compared. The drop-outs' reasons for terminating treatment are compared with the comments of patients who completed the therapy successfully. Drop-outs differ from successfully treated OCD's in five respects: they appear to be less obsessive-compulsive; they have more discongruent treatment expectations; they are more critical of the therapist; they experience less anxiety in carrying out homework assignments; they less frequently come under pressure from people close to them.