In 2002, Canada introduced routine, mandatory HIV antibody screening for all residency applicants, including selected children. We report screening results from January 2002 to February 2005. Thirty-six pediatric HIV cases were detected (14/100,000 applicants); 94% of infected children were eligible to arrive in Canada. Thirty-two of the affected children were from Africa, and maternal infection was the main risk factor. Only 4 (11%) of the children had received antiretroviral therapy. In countries of low HIV incidence, migration-related imported infection in children may be an emerging epidemic. The early identification of HIV-infected immigrant women permits intervention to prevent mother-to-child HIV transmission. Routine HIV testing as a component of the medical examination of immigrants has national and international health policy and programmatic implications.