This paper proposes the legal argumentation about legal basis of a father's shares in the family inheritence (waris) as ratified in the Indonesia's Compilation of Islamic Law. Using Islamic Law theoretical framework, it challenges the popular misconception that is expressed in the compilation that a mother and children have one-third shares after father's shares was given. Under this mode of thought, it is assumed that father's and male family member's shares are bigger that that of mother's and female family member's. In fact, it argues that the shares for all members of the family are the same: one-third.