Background General practitioners (GPs) are among the first health care providers to be involved in prediabetes care, and their actions can prevent patients’ transition from prediabetes to diabetes. However, data on knowledge and management of prediabetes in primary care remain scarce. Aim To describe the knowledge, attitudes and practices of GPs towards prediabetes. Design and setting This descriptive cross-sectional study included all private GPs working in Reunion Island. Method GPs were sent an electronic questionnaire that specifically sought to establish whether GPs knew the definition of prediabetes and whether their practices were in line with French guidelines for prediabetes screening and management. Results A total of 121 GPs completed the questionnaire. Of these, 95.0% knew the definition of impaired fasting glucose, but only 66.1% knew that of impaired glucose tolerance. Many GPs reported practices that are not recommended in guidelines. Thus, 59% of respondents declared that they monitored prediabetes with HbA1c and 10% said that they prescribed oral anti-diabetic drugs as prediabetes treatment. The risks factors associated with prediabetes were generally well known. Although 59.5% of respondents reported not having enough time to provide therapeutic education and medical follow up, only 19% referred their patients to a nutritionist or dietician. Lastly, 93.4% of respondents favoured the implementation of a local therapeutic education program targeting prediabetic individuals. Conclusion Prediabetes management in primary care can be made more effective by improving GPs’ knowledge of prediabetes and official guidelines, facilitating referral of prediabetic patients to lifestyle specialists and implementing local therapeutic education programs.