Objectives: Public health research on child health is increasingly focusing on the long-term impacts of infectious diseases, malnutrition and social deprivation on child development. The objectives of this exploratory study were to (1) implement the Ages and Stages Questionnaires (ASQ) in children aged 3 months to 5 years in a low-income Peruvian population and (2) to correlate outcomes of the ASQ with risk factors such as nutritional status, diarrhoea incidence and wealth index. Setting: Primary data collection was carried out in the Pampas de San Juan de Miraflores, a periurban lowincome community in Lima, Peru. Participants: The study population included 129 children selected through community census data, with a mean age of 22 months (SD 6.8) and with almost equal gender distribution (51% males). Intervention: A Peruvian psychologist administered the age-appropriate (ASQ2 for participants enrolled in 2009, ASQ3 for participants enrolled in 2010). Results of the ASQ are reported separately for five scales, including Communication, Gross Motor, Fine Motor, Problem Solving and Personal-Social. Primary and secondary outcome measures: For each scale, results are reported as normal or suspect, meaning that some milestone attainment was not evident and further evaluation is recommended. Results: Overall, 50 of 129 children (38.7%) had suspect results for at least one of the five scales, with the highest rates of suspect results on the Communication (15.5%) and Problem Solving scales (13.9%). Higher rates of suspect outcomes were seen in older children, both overall (p=0.06) and on Problem Solving (p=0.009), and for some scales there were trends between suspect outcomes and wealth index or undernutrition. Conclusions: The ASQ was successfully applied in a community-based study in a low-income Peruvian population, and with further validation, the ASQ may be an effective tool for identifying at-risk children in resource-poor areas of Latin America.