The family is the oldest human institution or social group that is developed due to the basic human needs, and has evolved in process of social change and transformations. The Iranian family, too, in its long history, has undergone major evolutions, that have not been studied seriously. In this paper, using the conceptual framework of functionalism, we tried to study the state of the Iranian family and its structure under one of the most important periods of the Iranian history, i.e. under the "Median" Empire, the first Empire in western Iran. The findings show that in this period the dominant form of the family was extended family, embedded in a large family network. This family performed the functions of reproduction, socialization and education of offsprings, production and provision of family consumptions needs, and maintaining the security needs of family members. Moreover, Median marriage was out-group marriage, manged by the family elders. Also, women and men both were involved in economic activities in and outside of the family.