Objectives: This study aims to standardize the Korean Childhood Stuttering Test (KOCS), and to test the reliability and validity of the KOCS and to provide standards. Methods: The participants were 107 children who stutter and 107 normal children aged 4-12 years. The KOCS consists of a speech fluency assessment, observational assessment, and supplemental assessment. The speech fluency assessment consists of four speech tasks: rapid pictures naming, rephrasing sentences, structured conversation,

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... and narration. In each task, the number of stuttering (repetitions, prolongations, blocks) in the first three words of a child's utterance is scored. The observation assessment is a rating scale conducted by a child's parents, teachers, and an SLP, and consists of an observational measure of disfluency and associated behaviors. Finally, supplemental assessments can be used selectively as advanced evaluation of children's speech fluency. The reliability of the KOCS was measured by internal consistency, standard error of measurement and inter-rater reliability. As for the validity of KOCS; predicted validity and construct validity were measured. Results: First, the KOCS showed high reliability in terms of internal consistency, standard measurement error and reliability between score. Second, the KOCS had high predictive validity due to high AUROC (Area under a ROC curve), sensitivity, specificity, and positive predictive value. The construct validity was confirmed by low correlation with age, group difference between children who stuttering (CWS) and children who do not stuttering (CWNS) and significant but not too high correlation between sub-tests. Third, cut-off scores, standard scores, and percentile ranks were calculated based on the raw data of domestic CWS and CWNS. Based on raw score, the score range was calculated to interpret the severity of stuttering. Conclusion: It is important to develop a child stuttering test that can confirm the reliability and validity of the child stuttering test, and present standardized norms for domestic children. In particular, the KOCS will be useful in the field because the test procedure and scoring method is simple and takes less time.