As international travel to developing countries increases, more people seek medical advice concerning food and water-borne diseases, including typhoid fever. Prevention of typhoid fever in high-risk groups (travelers to endemic areas, laboratory workers and household contacts of typhoid carriers) should rely primarily on prevention of exposure. However, immunization is an important adjunct. The decision to immunize against typhoid fever should be individualized, taking into account the benefits versus the risk of possible adverse reactions. Cases of reactive arthritis have been associated with the heat-phenol inactivated 'whole cell' parenteral vaccine, but to our knowledge reactive arthritis has not been previously reported with the oral form (Ty21a). This is a report of HLA-B27 negative reactive arthritis occurring in two travelers after the administration of oral Ty21a typhoid vaccine.