Aim: To assess the accuracy of the Childhood Autism Rating Scale (CARS) through systematic review and meta-analysis. Method: Studies that provided quantitative values for the reliability and validity for all versions of CARS were searched through MEDLINE, CINAHL, PsycINFO, Embase, and OpenDissertations. Results: A total of 24 studies with 4433 participants were included in our analysis. Meta-analysis showed that the summary Cronbach's alpha regarding a team of physicians and psychologists or others subgroup, derived from six studies (952 participants), was considered to be acceptable at 0.90 (95% confidence interval, 0.87–0.92) with moderate heterogeneity. Analysis of two ‘low risk of bias’ studies on the criterion validity for CARS with a cut-off of 30 and DSM-IV resulted in sensitivity of 0.86 and 0.71 and specificity of 0.79 and 0.75. Interpretation: Through the results of the current systematic review and meta-analysis, the internal consistency can be considered to be acceptable for a team of physicians and psychologists or others subgroup. In terms of the criterion validity, the sensitivity was thought to be acceptable although the specificity was not, suggesting that CARS should be used along with other confirmatory tools. What this paper adds: The Childhood Autism Rating Scale can be considered as a supplementary diagnostic tool for autism spectrum disorder.