An effective health system is based on effective primary care, at the center of which is family medicine. Cancer prevention and screening are integral aspects of general practitioners skills. Prevention is linked with the notion of risk. The relationship between the general practitioner and his or her patient reinforces the prevention of the development of preventable risk factors. It also strengthens information on intrinsic risk factors for patients. The protective factors highlighted by the general practitioner can thus reduce the risk a little more. Screening strategies differs across cancers and countries. In France, general practitioner's involvement is important for colorectal cancer screening. The active participation of their general practitioner, strengths patient's adherence and participation. Their role is to inform and collect data for breast cancer screening. Recently organized cervical cancer screening requires greater involvement of general practitioners who can act as both actors and informants. Family medicine is at the heart of cancer prevention and screening. It is a central hub for improving the health of patients in our healthcare system. The general practitioner knows the patient, which gives him an important advantage to accompany him in the prevention and screening of his risk factors.