With a growing understanding of genetic disorders in the scientific and lay literature, it is becoming increasingly important to consider risk factors based on family history and ethnicity for identifying individuals for whom genetic testing is indicated and will be most beneficial. A pedigree helps to identify patients and families who have an increased risk for genetic disorders, to optimize counselling, screening, and diagnostic testing, with the goal of disease prevention or early diagnosis and management of the disease. Information should be updated periodically as new information regarding family history is acquired. This review was designed to provide a rationale for and an approach to obtaining a three-generation pedigree for patients who are seen as new assessments or those under ongoing care by primary care or specialist physicians, as well to summarize some resources available for constructing a useful pedigree.