Introduction: There is a plea for the development of tools allowing the screening of fragile patients under oral chemotherapy. Such tools would identify patients with difficulties for being adherent or for having low side effects management skills. The aim of this study is to validate psychometric characteristics of a questionnaire assessing patients' adherence and skill level of management for oral capecitabine treatment. Methods: Questionnaire's psychometric validation study. Prospective monocentric cohort. Cases-simulated questionnaire was constructed, according to recommendations, from the results of a socio-anthropological study. Validation phases included: a pre-testing and a field-testing including acceptability, scale reliability and internal consistency were conducted involving experts and patients sample.Results: Pre-testing excluded 1 item. Acceptability phase included 15 patients, who did not change any of the questions. Reliability and internal consistency were tested with 67 patients. Cancer site did not statistically influence questionnaire answers. No correlation was identify with the analyse performed for the internal consistency testing.Conclusion: This questionnaire has shown to be a valid tool for the assessment of the adherence and side effect management skill for patients with capecitabine treatment. It can easily be uses as a screening tool for prescribers. It can also be used as an evaluation tool for a therapeutic education programme in this field.