Abstract: This study is taken from the study of marginalization cases experienced by Pakpak women of rural poor families. The study was conducted in Pegagan village of Sumbul subdistrict, Dairi, North Sumatra Province. The marginalization phenomenon is shown in some aspects, restrictions on women's access to formal education, tendency of dropping out of school having no in heritance rights and no role in the decision making of custom. Related to this phenomenon, the research question of this study is how the process of marginalization experienced by women in their familyis. Marxist structural feminist perspective and qualitative approach with feminist perspective were used to answer the research question. The findings of the study finally, show that the structured patriarchy ideology as gender ideology in family becomes the cause of women marginalization. Patriarchy becoming gender ideological construction in Pakpak family is interpreted and expressed in the form of private patriarchy that is a hegemonizing system or structure of men power that has dominated and sub-ordinated social position of women in Pakpak families.