PDS 72: Environmental health issues in LMIC, Exhibition Hall (PDS), Ground floor, August 28, 2019, 10:30 AM - 12:00 PM Background/Aim: Colombia is one of the Latin American countries with the highest rates of childhood cancer. Our objective was to conduct a national spatial analysis of potential clusters of acute childhood leukemia (ACL) and explore their spatial relationship with industrial air pollution sources in two metropolitan areas of Colombia. Methods: Data of incident cases of ACL during 2009-2017 was obtained from the National Public Health Surveillance System and confirmed by the National Cancer Registry using the municipality as spatial unit of analysis. Analyses of ACL in the metropolitan areas of Bucaramanga and the city of Medellín during 2000-2015 were conducted at sector-census level using validated data from the local population-based cancer registries. Industrial pollution sources data were obtained from the environmental local authorities. The Kulldorff's circular scan test was used in its localized non-focal version for the national analysis and in the localized focal-version for the analysis in the metropolitan areas using the centroids of the main industrial zones as putative sources of pollution. Multivariable Poisson models of ACL rates were built using distance and direction to industrial sources as spatial variables while adjusting for socioeconomic status. Results: Seven clusters of ACL were identified in the national spatial analysis, including two clusters in the metropolitan area of Bucaramanga and the city of Medellín. The Kulldorff's localized focal test found significant spatial clusters (p<0.001) around one industrial area in Bucaramanga and two industrial areas in Medellín. The multivariable models results suggest that the distance effect of the industrial areas is modified by the directional effect of the wind. Conclusion: Spatial clusters of incident cases of ACL were identified around three industrial areas in the cities of Bucaramanga and Medellín. Our findings support the hypothesis that ACL might be related with industrial pollution emitted to the air in Colombia.