PURPOSE The family history is becoming an increasingly important feature of health promotion and early detection of common chronic diseases in primary care. Previous studies of patients from genetics clinics suggest a divergence between how persons with a family history perceive and understand their risk and the risk information provided by health professionals. This interview study aimed to explore how patients in primary care understand and come to terms with their family history of cancer, heart disease, or diabetes and how family history might affect consultations about disease risk and management. \METHODS Thirty semistructured interviews were conducted with general practice patients who had a family history of cancer, heart disease, or diabetes. The transcript data underwent a qualitative constant comparative analysis.RESULTS What exactly constitutes having a family history of an illness varied among participants. The development of a personal sense of vulnerability to the illness in the family depended not only on the biomedical approach of counting affected relatives but also on a sophisticated interplay of other factors. The emotional impact of witnessing the illness in the family, particularly if the illness was sudden, premature, or fatal, and the nature of personal relationships within a family that determine a sense of emotional closeness and personal likeness with the affected relative, all contributed to the perception of disease risk. Different beliefs about the contributions of nature and nurture to disease can affect patients' views on he degree of control they can exert over their risk.CONCLUSION This study highlights potential differences between the way patients and medical professionals assess and understand familial risk of cancer, heart disease, and diabetes. Our previous systematic review findings are enhanced by showing that personal experience of disease and the emotional impact can also influence familial risk perceptions. Eliciting the patient's perspective when discussing risk of chronic disease, particularly in the context of a family history, could inform a more patient-centered approach to risk assessment and communication and support patients to make informed decisions about the management of their disease risk.