Objective The primary goal of this study was to examine the factor structure of a spina bifida (SB) medical responsibilities measure and a medical regimen skills scale across time in families of youth with SB. Method One-hundred and forty youth with SB and their parents were assessed in both childhood/adolescence and adolescence/young adulthood. The Sharing of SB Medical Responsibilities Scale (SOSBMR) includes 34 items for which participants indicate who is responsible for each task. The SB Independence Survey (SBIS) is composed of 50 SB-specific medical skills items in yes-no format. Confirmatory factor analyses (CFA) were conducted to examine the factor structure of the SOSBMR and SBIS in childhood and adolescence (ages 8–15) and in adolescence/young adulthood (AYA; ages 16–25). Results One- and seven-factor CFAs were compared for both measures. For the SBIS, both mother- and father-report were used in childhood; self-report was employed for AYA. For the SOSBMR, only self-report was used for both age groups. Across each rater and time point, the seven-factor models of the SBIS and SOSBMR had adequate to excellent fit and reliability, indicating the ability to use each subscale. In addition, each of the corresponding subscales on the SOSBMR and SBIS were associated with each other across raters and time, showing good concurrent and predictive validity. Conclusions From childhood to young adulthood, the subscales of the SOSBMR can be used to examine responsibility across multiple medical tasks and the SBIS can be used to assess medical regimen skills and mastery in young people with SB.