non-existing capacity. Accordingly, complete performance capacity is the validity of human beings to behave in a manner that does not depend on the opinion of others, while the incomplete performance capacity is the validity of human beings to behave in a manner for certain acts without the other ones and thus the capacity to perform is incomplete. In other words, we are concerned here with the performance capacity and not the obligation capacity. Article (47) of the Civil Law No. (43) of 1976 stipulates that no one my waive his/ her personal freedom or capacity or amend its provisions. Moreover, the text of Article (116) stipulates that every person is eligible for concluding contracts, unless deprived or restricted of capacity by virtue of law. Mental disability (the "insanity" in legal terms of the law) is considered one of the aspects of legal capacity and it is clear that mental disabilities are classified into three categories or classes: First, the class with severe disability, where there is a risk of making wrong decisions detrimental to their interests. Second, the class with medium disability, which can make decisions that take place between benefit and damage. Third, the class with simple disability, which can make the right decisions, but this does not always mean right decisions as is the case with others. The legislator determines the custodian or guardian for persons with disabilities, as the custody is on the soul and funds and is granted to the father, mother, grandfather or the court. The custody includes the ability to conclude contracts, marriage, and disposition of funds and benefits. In other words, it gives the custodian the right of disposition of the funds of the person under custody. However, in the case of marriage, the Personal Status 23