Morbid jealousy is a relatively common problem that often results in relational conflicts, frequently involving violence. Eventually many relationships break down as a consequence of these conflicts. Despite of this morbid jealousy is considered to be under-researched. As regards the treatment of morbid jealousy there is however some evidence that cognitive behaviour therapy is a worthwhile treatment, and there is also a growing body of evidence that jealousy, normal as well as morbid, is an evolutionary adaptation. This study integrates an evolutionary psychological approach with cognitive behaviour therapy in the treatment of morbid jealousy.