Aim: This study assessed the effect of the paradox in family therapy. The paradox, as a therapeutic tool, has been developed by a number of therapists, especially Mara Selvini Palazzoli. Cases: Two clients (both female) were chosen for this study. These two girls were the symptomatic members of their families. They were both depressed and on medication for more than two years. Management and outcome: The therapist benefited the Milan Systems Approach to family. The families participated in 16 sessions of therapy. Then, they were followed up for two years. All family members filled in FAD and BDI questionnaires before the therapy, in the tenth session, after therapy and three months later. It was found that the paradox in appropriate cases had satisfactory outcome. This method reduced the symptomatic behavior, and affected family system as a whole. Family system became more workable and functional. Case 1 after two years was well functioning and got married. Case 2, after therapy, did not need to take medication, finished her high school and entered university. Conclusion: The paradox is a powerful tool for family therapy. It is a creative and critical solution for long-term illness. But Caution should be taken when using this technique in therapy. It should be the last option in the course of family therapy, after other techniques failed to be effective.