OBJECTIVE: To analyze and compare Modified Checklist for Autism in Toddlers (M-CHAT) and Checklist for Autism in Toddlers-23 (CHAT-23) in terms of clinical applicability, and to provide a basis for the understanding of early specific clinical manifestations of children with autism. METHODS: A total of 350 children aged 18-36 months who visited the Department of Developmental Pediatrics of Shengjing Hospital of China Medical University were enrolled as subjects. Of the 350 children, 284 who had not been previously diagnosed with autism were screened according to the two checklists. Sixty-eight confirmed cases of autism (including two of the 284 screening subjects diagnosed with autism) were assigned to the autism group, and 278 of the 284 screening subjects (except six children diagnosed with autism, mental retardation or cerebral palsy) were assigned to the control group. The two groups were compared with respect to the positive rate for each item in the checklists. The efficacy of the M-CHAT and CHAT-23 assessment criteria was evaluated by comparative analysis. RESULTS: The autism group showed the highest positive rate for Item 9. There were significant differences between the two groups in terms of the positive rates for all items except Item 16 (P0.05). CONCLUSIONS: CHAT-23 is more suitable than M-CHAT for clinical autism screening due to higher specificity, as well as having the advantages of low cost, easy completion,high efficiency and easy result judgment.