Each year, approximately 50,000 foreign-born children immigrate to Canada, with more than 7,000 in the province of Quebec. An understanding of the infectious diseases affecting these children is essential to provide adequate health care. There are few published data about infectious diseases in immigrant children. To determine the type and prevalence of infectious diseases in immigrant children presenting at a tertiary pediatric care center. We conducted a retrospective chart review of children presenting within one year of arrival in Canada, between 01/01/98 and 31/12/01 at the Immigrant Health Clinic of Sainte-Justine Hospital in Montreal. Demographic data, growth parameters, tuberculin skin test (TST), hepatitis B, C and A, HIV and syphilis serologic profiles, stool examinations for ova and parasites, and stool cultures were reviewed. Microsoft Excel Office XP and SPSS software were used for data compilation and analysis. Of the 110 children evaluated, 60 (55%) were girls. Median age at evaluation was 5.5 years (range: 0.2–18.6 years). The children immigrated from North Africa (25%), sub-Saharan Africa (23%), Asia excluding mainland China (23%), Haiti (15%), Middle East (6%), China (2%), Eastern Europe and former Soviet Union (2%). Most of the children had appropriate weight and height for age. BCG was documented in the chart in 38% of all patients (42/110). TST was performed in 87 children. Thirty-three of the 64 (52%) available results had a reaction =10 mm; all had normal chest x-rays and were treated with isoniazid. No patient was HBsAg positive. Four patients were anti-HBc positive but only one had serologic evidence of acute hepatitis B infection with positive IgM anti-HBc, although asymptomatic. Thirty-nine of the 107 (36%) tested had anti-HBs antibodies. One (0.9%) of the 106 children tested positive for hepatitis C IgG. No patients had a serologic profile of acute hepatitis A. Three of the 106 children tested positive for HIV serology (2.8%), and were infected. All of the 103 children screened for syphilis were negative. Stool parasites were found in 39% (30/76) of patients and 22.4% (17/76) were considered pathogenic. Giardia lamblia was the most common parasite (13%). Stool cultures were negative in all tested children (n=27). This study shows a significant prevalence of infectious diseases in our population of immigrant children. Overall, 1/2 immigrant children has positive TST, 1/5 harbours pathogenic parasites, 1/33 has HIV, 1/100 has acute hepatitis B and 1/100 has hepatitis C.