Transition of care for adolescents includes a transfer from paediatric to adult health care. This requires a transfer of specific measurements, which evaluate disease profiles such as functional ability. One of the most common measurements is the Health Assessment Questionnaire (HAQ).Results of the Childhood HAQ (CHAQ) and HAQ were compared among adolescents diagnosed with rheumatic diseases involving the musculoskeletal system. All adolescents had recently dealt with or would in the near future be dealing with transition.Overall results of both questionnaires were comparable; intra-class correlation for consistency (ICC) was 0.95 (95% confidence interval 0.93-0.97). For a smooth transfer from CHAQ to HAQ, both correlation and agreement are required. Agreement between both questionnaires was not found. Described by limits of agreement, results of HAQ can differ from CHAQ as much as 0.95.Despite strong correlations for consistency, lack of agreement was found in the results of CHAQ and HAQ. If correlation persists over time, this study suggests evaluating both the childhood and adult version of the HAQ during the transition period. When transfer into adulthood is completed, comparison to earlier tests at younger age is available and reliable.