The convergence of Islam among the Muslims increased every year. This development is excellent and shows that Islam is a religion of mercy and is appropriate for all ages. The term mualaf or sibling is often used by the community or agency that manages, guides and protects the welfare of the mualaf. There are questions about the duration of the status different caliphs by state which lead to the need for the status caliphs to be studied in detail. Therefore, the objective of this study is to identify the concept of mualaf and mukalaf according to the criteria set by Islamic scholars in defining a person as a mukalaf. This study will also examine the methodology for determining the status of mualaf to mukalaf based on the views of scholars and current needs. This study uses a qualitative approach to the documentation method. The results show that the method of determining the status of a mualaf to a mukalaf must meet the three main criteria, namely maturity, reason, and understanding of a given law. Further study of additional measures in determining the status of the mualaf to the mukalaf should be done to develop an instrument that can be used by the relevant agency. It is hoped that this study will serve as a reference and guide to the zakat management in Malaysia in developing the method of determining the status of mualaf to the mukalaf