In France, cancers are the leading causes of death in men and in women aged to 35 to 65, and the cancer incidence in Picardy area is among the highest in France. General practitioners can play a key role in prevention and early detection of cancer. The aim of this study was to assess their current clinical practices concerning risk factors like tobacco, alcohol, diet, sun exposure and cancer screening. A questionnaire on primary prevention and cancer screening practices of general practitioners (GP) in the Picardy area was administered to 480 GP (31%). Questions concerned primary prevention (tobacco, alcohol, diet, sun exposure) and cancer screening (breast, uterine cervix, colon-rectum, prostate, other cancers). In addition, the GP were also interviewed on difficulties encountered in their practice and about their perception of the prevention actions. Smoking prevention is the best structured primary prevention action, unlike alcohol prevention and advice on diet seem to be more difficult strategies. We noted a great diversity for screening, even for cancers with a consensus, like breast, uterine cervix and colon-rectum cancers. Lot of physicians reported ordering prostatic specific antigen test (91%) but are only 5% to have fecal occult blood tests. 83% of the GP screened their patients on skin cancer at least once a year. These findings suggest that general practitioners can play a key role in prevention and early detection of cancer, but have difficulties like lack of time, lack of expertise or non compliance of their patients.