To compare the inter-rater reliability, concurrent validity, completion time, and ease of use of two methodological quality (MQ) assessment tools for cross-sectional studies: an adapted Newcastle-Ottawa Scale (NOS) and the Appraisal Tool for Cross-Sectional Studies (AXIS).Two raters applied the NOS and AXIS to 63 cross-sectional studies of health-related quality-of-life and breast cancer.AXIS demonstrated poor inter-rater reliability (intraclass correlation coefficient [ICC] = 0.49) and required more than double the amount of time to complete compared to the NOS, which demonstrated moderate reliability (ICC = 0.73). For concurrent validity, weak and moderate positive relationships existed between NOS and AXIS (rater 1: r = 0.26; rater 2: r = 0.45). Ease of using the tools was affected by the indirectness of MQ assessments, perceived thoroughness of the tools' content, and user experience.This study was the first to assess the psychometric properties of a cross-sectional NOS and AXIS. The results did not support a clear choice between selecting either tool for evaluating MQ in cross-sectional studies.