The awareness and knowledge of developmental milestones among health practitioners need to be enhanced to better enable early identification and intervention with children who have delays in development, intellectual deficit, and developmental disabilities and are residents in low-and middle-income countries. To meet this end, a simple one-page check-off developmental milestone chart for age groups birth to eight years was developed as an outgrowth of a training program for pediatricians in Cambodia. Expected milestones for gross motor, fine motor, language, and social development were charted for each age group, and then validation trials were performed in an outpatient clinic over two years. It was observed that 25% and 31.5% of children failed to achieve one or more age-appropriate developmental milestones in trials held in 2007 and 2008, respectively. The author observes that referral for further evaluation, parental education/support, early child care, and early intervention would need to be based on subsequent trials of more culturally accurate local milestones, and further studies to determine an acceptable number of milestone failures that would yield the least false positives. Similar processes for developing instruments, utilizing local culturally appropriate developmental milestones, are recommended for training purposes and regular clinic use in other low- and middle-income countries.