Background A range of preventive practices are recommended to reduce the burden of chronic diseases. The aim of our study was to describe the preventive practices of French-speaking primary care physicians. Methods A cross-sectional survey was conducted in 2015 in a randomly selected sample of 1100 primary care physicians (700 in Switzerland, 400 in France). The physicians were asked how often they performed the following recommended preventive practices: blood pressure, weight and height measurements, screening for dyslipidemia, screening for alcohol use and brief intervention, screening for smoking (and brief advice for smokers), colon and prostate cancer screening, and influenza immunization. Response options on the five points Likert scale were never, rarely, sometimes, often, always. The physicians were considered to be performing the preventive practice regularly if they declared performing it often or always. Results 518 participants (47%) returned the questionnaire. The most commonly reported preventive practices were: blood pressure measurement (99%), screening for smoking (95%) and brief advice for smokers (95%). The least frequently reported practices were annual influenza immunization for at-risk patients <65 years (37%), height measurement (53%), screening for excessive alcohol use (60%) and brief advice for at-risk drinkers (67%). All other practices were reported by 70 to 90% of participants. PLOS