Context: Influenza vaccination is recommended every winter for at-risk populations with the aim for public health of 80%. This rate has never been reached; people under 65 with chronic disease are even the population with the lowest rate of influenza vaccination. (35.9% in 2014/2015 and 33.3% in 2013/2014). Method: a retrospective survey has been conducted in Gironde (France) among chronic disease patients under 65 to discover the reason why they would refuse influenza vaccination. Results: 47.8% of the non-vaccinated patients are sceptical about the efficiency of the vaccine. The fear of undesired effects of the influenza vaccine and the fact of considering influenza as a benign disease are sufficiently important factors for not getting vaccinated for 41.3% and respectively 32.6% of non-vaccinated patients. The number of consultations with the general practitioner does not influence the vaccine statuts. Patients with chronic disease under 65 and vaccinated do it to protect themselves above all (98.8%) and to protect their relatives from the flu (81.3%). Conclusion: patients under 65 with chronic disease still have too many false beliefs against influenza vaccination regarding its efficiency and undesired effects, as well as the riskiness of the disease.