ObjectiveTo evaluate the association between gifts from pharmaceutical companies to French general practitioners (GPs) and their drug prescribing patterns.DesignRetrospective study using data from two French databases (National Health Data System, managed by the French National Health Insurance system, and Transparency in Healthcare).SettingPrimary care, France.Participants41 257 GPs who in 2016 worked exclusively in the private sector and had at least five registered patients. The GPs were divided into six groups according to the monetary value of the received gifts reported by pharmaceutical, medical device, and other health related companies in the Transparency in Healthcare database.Main outcome measuresThe main outcome measures were the amount reimbursed by the French National Health Insurance for drug prescriptions per visit (to the practice or at home) and 11 drug prescription efficiency indicators used by the National Health Insurance to calculate the performance related financial incentives of the doctors. Doctor and patient characteristics were used as adjustment variables. The significance threshold was 0.001 for statistical analyses.ResultsThe amount reimbursed by the National Health Insurance for drug prescriptions per visit was lower in the GP group with no gifts reported in the Transparency in Healthcare database in 2016 and since its launch in 2013 (no gift group) compared with the GP groups with at least one gift in 2016 (−€5.33 (99.9% confidence interval −€6.99 to −€3.66) compared with the GP group with gifts valued at €1000 or more reported in 2016) (P<0.001). The no gift group also more frequently prescribed generic antibiotics (2.17%, 1.47% to 2.88% compared with the ≥€1000 group), antihypertensives (4.24%, 3.72% to 4.77% compared with the ≥€1000 group), and statins (12.14%, 11.03% to 13.26% compared with the ≥€1000 group) than GPs with at least one gift between 2013 and 2016 (P<0.001). The no gift group also prescribed fewer benzodiazepines for more than 12 weeks (−0.68%, −1.13% to −0.23% compared with the €240-€999 group) and vasodilators (−0.15%, −0.28% to −0.03% compared with the ≥€1000 group) than GPs with gifts valued at €240 or more reported in 2016, and more angiotensin converting enzyme (ACE) inhibitors compared with all ACE and sartan prescriptions (1.67%, 0.62% to 2.71%) compared with GPs with gifts valued at €1000 or more reported in 2016 (P<0.001). Differences were not significant for the prescription of aspirin and generic antidepressants and generic proton pump inhibitors.ConclusionThe findings suggest that French GPs who do not receive gifts from pharmaceutical companies have better drug prescription efficiency indicators and less costly drug prescriptions than GPs who receive gifts. This observational study is susceptible to residual confounding and therefore no causal relation can be concluded.Trial registrationOSF register OSF.IO/8M3QR.