OBJECTIVES: To understand how neighbourhood characteristics affect the health of immigrant children in Canadian cities. We question whether the health of children is influenced by immigrants living in enclaves of people with similar ethnic and socio-economic backgrounds. METHODS: Two datasets were used: the New Canadian Children and Youth Study (NCCYS) and Statistics Canada census data. The NCCYS comprises children from Hong Kong, the Philippines and Mainland China living in Canada's largest cities. Logistic regression was used to examine the influence of neighbourhood ethnic concentrations and mean income on health. RESULTS: Girls were more likely to be reported to have excellent health compared to boys, as were children living in neighbourhoods with lower mean parental education. Children from Hong Kong were less likely to have excellent health compared to the reference group. For the Mainland Chinese group only, there was an inverse relationship between reported health status and the concentration of people from the same ethnic background in the neighbourhood. CONCLUSION: The health of children from different ethnic backgrounds is influenced by different social and economic factors. In practice and in research, "immigrants" and even broadly defined cultural groupings, such as "Asian immigrants", should be considered as heterogeneous. [Copyright of Canadian Journal of Public Health is the property of Canadian Public Health Association. Full article may be available at the publisher's website: http://journal.cpha.ca/index.php/cjph/issue/archive]