Abstract: Genealogy is a piece of activity relating to the research of a descendant of a family or a person. At present, genealogy research activity especially in the context of Malay society is carried out manually. This study describes the definition of 23 genealogy rules created to enable the generation of the Malay family relations by a genealogy system and the detection of the family relation using the tree concept or tree technique. These rules would be used in the genealogy database and are formalized to show the structure of nodes involved in determining a family tree.