OBJECTIVES: International immigration to Chile has increased in the past decade. Preliminary analysis found the immigrants were a very heterogeneous and polarized group in their SES which makes it difficult to identify particular needs of vulnerable subgroups within the total immigrant population. This analysis aims to describe their SES patterns. METHODS: Cross-sectional Chilean survey (CASEN-2006). From 268,873 participants, one percent were immigrants (n=1.877). Cluster analysis identifies subsets of a data set that contain similar points. Replacing these subsets by their aggregate properties, it creates a compact representation of the data set as a group of clusters. Hierarchical clustering is a step-wise process that merges the two closest or furthest data points or groups of data points at each step. Among the different types of hierarchical cluster analyses available, complete-linkage method was chosen as it creates clusters from the most distant values of the selected attributes (income, education and employment-status). Each SES-cluster was analysed in its demographic (age/sex/marital-status), geographical (urban-rural/region), SES variables (income/education/occupation), material-standards (overcrowding/sanitary-conditions/housing-quality). Analysis in STATA 10.0. RESULTS: After conducting complete-linkage hierarchical cluster analysis, three groups were identified: High-SES (n=398), Medium-SES (n=889), Low-SES (n=587). Key patterns are: High-SES: mean 35 years-old, 90% of working age, most married, technical or university level, only 2.7% with ethnic background. Medium-SES: mean 33 years-old, >60% technical education, mixed cluster. Low-SES: mean 25 years-old, >60% women, 8% ethnic background, up to high-school only, 2 poorest income quintiles. CONCLUSIONS: Immigrants in Chile are a very heterogeneous group, polarized by their SES. Hierarchical cluster analysis provided an appropriate method to group immigrants according to their socio-economic characteristics and, consequently, to provide clear patterns of SES vulnerability within the total immigrant population. Immigrants living in the Low-SES cluster are a vulnerable group that needs further attention in Chile.