OBJECTIVE: STOPP-START is a screening tool for detecting inappropriate prescriptions in older people. Recently validated in its English-language version, it is a reliable and easy-to-use tool, allowing assessment of prescription drugs often described as inappropriate (STOPP) or unnecessarily underused (START) in this population. An adaptation of the tool into French language is presented here. METHOD: A translation-back translation method, with validation of the obtained version by French-speaking experts from Belgium, Canada, France and Switzerland, has been used. An inter-rater reliability analysis completed the validation process. Fifty data sets of patients hospitalized in an academic geriatrics department (mean age +/- standard deviation: 77.6 +/- 7.9 years; 70% were women) were analyzed independently by one geriatrician and one general practitioner. RESULTS: The adaptation in French considers the 87 STOPP-START criteria of the original version. They are all organized according to physiological systems. The 50 data sets involved 418 prescribed medications (median 8; inter-quartile range 5-12). The proportions of positive and negative inter-observer agreements were 99% and 95% respectively for STOPP, and 99% and 88% for START; Cohen's kappa-coefficients were 0.95 for STOPP and 0.92 for START. These results indicated an excellent inter-rater agreement. CONCLUSION: Therefore, this French language version of STOPP-START is as reliable as the original English language version of the tool. For STOPP-START to have tangible clinical benefit to patients, a randomized controlled trial must be undertaken to demonstrate efficacy in the prevention of adverse clinical events connected with inappropriate prescriptions.