Research in diagnostic accuracy studies (DAS) is a rapidly developing area in medicine, but there are only three instruments used in this scenario. The aim of this study was to design and validate a scale to determine methodological quality (MQ) of DAS. Scale validation study. A systematic literature review about the MQ of diagnostic accuracy studies was accomplished, and an expert panel generated a first draft (content validity) of the scale. An alphanumeric order was given and rated by six researchers (second draft) and a pilot study to optimise its use and understanding was performed (third draft). Two independent researchers applied the final scale (9 items/3 domains) to 110 articles from 13 journals with high, medium and low impact factors. Criterion validity was determined by contrasting MQ scores with the Oxford Centre for Evidence-Based Medicine levels of evidence. The construct validity of the extreme groups and high and low IF were estimated. The intraclass correlation coefficient was used to determine inter-observer reliability, and the cut-off point was calculated using a ROC curve. The best cut-off point was 24 points, with an under curve area of 93.4 %. The content validity rating was 80–100 % for all included items. Criterion and construct validity were statistically significant with p<0.05. Interobserver reliability was estimated in 0.96. A scale to measure the MQ of DAS was designed and validated.