Due to the changes are generally happened in the architecture and the architectural design process, and especially in the inheritance houses design fields. Because of the large increase in the demands for houses in the world. In Addition to that, the imported concepts and shapes from the foreign architecture in the Islamic Arabic architecture. The Islamic inheritance houses had suffered from the problem of contemporary transformations and threat urban structure. For the previous reasons this research will discuss the research problem which is; what are the characteristics of sustainable efficient spaces in Islamic inheritance houses. The research objective is to explore the sustainable traditional efficient elements to use it in the contemporary hosing; to sustain the Islamic traditional heritage and Islamic identity. This Study has a try to investigate the pheno-type and geno-type of the sustainable efficient spaces of Islamic inheritance houses (tradition inheritance houses). Research methodology will be inductive method through making surveying for the efficient spaces in selected traditional cases study in Arabian cities. Five distinguished inheritance houses in Bahrain as cases study have been selected: “Sheikh Issa Ibin ali Inheritance houses”, “Seiady Inheritance houses in Moharaq”, “the inheritance houses of Sheikh Salmaan”, “the inheritance houses of Ahmed Khalaf” and “the inheritance houses of Yusuf Redha in Manama”. These five inheritance houses are similar to many Islamic inheritance houses in Arabian cities and they are the most Islamic traditional reputed inheritance houses in the Gulf area. The study has try to investigate pheno-type, geno-type for the efficient spaces in Islamic inheritance houses. The study finds number of pheno-types, genotypes and another characteristic for sustainable efficient elements. The research finds that; the genetic features in the Islamic selected inheritance houses have three efficient spaces. The efficient spaces are “specific, specific-general and general”. Those spaces are opened to a certain courtyard, or they are sharing the same one. And probably one of the previous spaces has more than one courtyard. So; there are clear separation for these efficient spaces in the Islamic inheritance houses, through the concept of the hierarchy from (Specific spaces) then (Specific-General spaces) then to the (General spaces). All selected inheritance houses have another characteristic; they have the fact that the privacies in the ground floor is less than the privacy in the first floor.