Introduction. The transition of adolescents with chronic conditions to adult follow-up care is an increasingly complex process. Patients need to acquire knowledge and skills that ensure continuity of their care. The goal of this study was to validate the Argentinian Spanish version of the Transition Readiness Assessment Questionnaire (TRAQ) 5.0 tool in adolescents and young adults with chronic conditions. Population and methods. Descriptive, crosssectional, quantitative study. Patients with chronic conditions aged 14 years or older treated at Hospital Garrahan were included. The TRAQ is made up of 20 items divided into 5 subscales (Managing Medication, Appointment Keeping, Tracking Health Issues, Talking with Providers, Managing Daily Activities), and is designed to be self-administered. Patients completed the TRAQ, as well as an opinion survey about its use and a self-perceived autonomy scale; their physicians answered a scale about patients' health impairment due to the condition. Sociodemographic, clinical and TRAQ-related variables were recorded. Results. A total of 191 patients participated. The majority of patients (96.3%) understood the TRAQ 5.0 questionnaire and completed it correctly, in self-administered modality, in a short time (median: 5 minutes), with little or no help (81%). Patients who live in poverty or have a lower education level than the one expected for their age needed more help. Internal consistency (Cronbach's alpha) for the overall score was 0.81. Construct validity was demonstrated by testing different hypotheses (all p < 0.05): discrimination by age ≥ 16 years (3.01 vs. 3.34), sex (women: 3.38 > men: 3.12) and having plans for the future (without plans: 3.01 < with plans: 3.34); correlation with self-perception scale (r= 0.49). Conclusion. The TRAQ 5.0 tool is available for use in Argentinian adolescents with chronic conditions.