Child growth is a dynamic process and has different stages including the development of gross motor, fine motor, communication, and personal-social abilities. Developmental disorders as one of the most common problems in the process child growth This study aimed to determine the developmental level of infants under two years who were admitted to the health care centres' of Kurdistan University of Medical Sciences, in Sanandaj in 2009. This descriptive, cross-sectional study was done with a systematic method by using standard Age and Stages Questionnaires( ASQ) on 397 children aging 4 to 24 months. The collected data was analyzed using SPSS 13 software and was described with frequency and percentages values. Finally, data was analyzed via Fisher's exact test. The mean prevalence of developmental delay was 4.8 203 girls and 194 boys, in other words 3.9 and 5.7 percent, respectively. The prevalence of developmental delay was 11.4% in four months old children in four domains, 5.7% in 6 months old children in two domains, 34.4% in 18 months old children in three domains, and 5% in 24 months old children in one domain. According to this study, the developmental delay was in an acceptable level, however, it increased dramatically at the age of 18 months. The highest level of developmental delay was observed in fine motor. Educating parents and encouraging primary care providers like, family physicians and pediatricians can increase early detection and reduce the prevalence developmental delay in children.