BACKGROUND: Increasing international migration may challenge healthcare providers unfamiliar with acute and long latency infections and diseases common in this population. This study defines health conditions encountered in a large heterogenous group of migrants. METHODS: Migrants seen at GeoSentinel clinics for any reason, other than those seen at clinics only providing comprehensive protocol-based health screening soon after arrival, were included. Proportionate morbidity for syndromes and diagnoses by country or region of origin were determined and compared. RESULTS: A total of 7629 migrants from 153 countries were seen at 41 GeoSentinel clinics in 19 countries. Most (59%) were adults aged 19-39 years; 11% were children. Most (58%) were seen >1 year after arrival; 27% were seen after >5 years. The most common diagnoses were latent tuberculosis (22%), viral hepatitis (17%), active tuberculosis (10%), human immunodeficiency virus (HIV)/AIDS (7%), malaria (7%), schistosomiasis (6%), and strongyloidiasis (5%); 5% were reported healthy. Twenty percent were hospitalized (24% for active tuberculosis and 21% for febrile illness [83% due to malaria]), and 13 died. Tuberculosis diagnoses and HIV/AIDS were reported from all regions, strongyloidiasis from most regions, and chronic hepatitis B virus (HBV) particularly in Asian immigrants. Regional diagnoses included schistosomiasis (Africa) and Chagas disease (Americas). CONCLUSIONS: Eliciting a migration history is important at every encounter; migrant patients may have acute illness or chronic conditions related to exposure in their country of origin. Early detection and treatment, particularly for diagnoses related to tuberculosis, HBV, Strongyloides, and schistosomiasis, may improve outcomes. Policy makers should consider expansion of refugee screening programs to include all migrants.