Objective: The Parents' Evaluation of Developmental Status (PEDS) and the Ages and Stages Questionnaire (ASQ) are developmental screening tools that are commonly used in pediatric practice worldwide. We aimed to compare the screening results of the PEDS and the ASQ in children with a wide range of ages and to evaluate the degree of agreement between the tests across the age groups. Methods: The study was conducted with the participation of 327 children aged 3 to 72 months. Participants were administered the PEDS and then the ASQ. Children with known developmental disabilities were included in the study to represent a real-world clinical practice setting and evaluated with a clinical workup. Results: The median age of the children was 35.1 months, with a range of 3 to 72 months. The percentage of children with known developmental disabilities was 16.5%. The actual agreement between the PEDS and ASQ was 74% with a concordance represented by Cohen kappa of 0.422 (p < 0.001) in the total sample. Furthermore, the agreement was higher in children aged 25 to 36 months and 37 to 48 months than for the other ages. Conclusion: We compared the clinical features of the ASQ and PEDS across the age groups, and they demonstrated moderate agreement. The present study also showed the performance of the PEDS and suggests that it should certainly be used for developmental screening in routine child health care practice in Eurasia, thus supporting the use of such parent-completed developmental tools that should be encouraged for universal screening.