During the 2000-2001 influenza immunization campaign in Canada, a new adverse event, oculo-respiratory syndrome (ORS), was noted in association with administration of vaccine supplied by one manufacturer. The original case definition for ORS specified bilateral conjunctivitis, facial edema, or respiratory symptoms beginning 2-24 h after influenza vaccination and resolving within 48 h after onset. To characterize the spectrum, severity, and impact of ORS, we contacted persons who had reported any influenza vaccine-associated adverse event in British Columbia, Canada, during the 2000-2001 vaccination campaign. With use of a standardized telephone interview, we collected information from 609 (79%) of 769 eligible persons. Thirteen percent of ORS-affected persons reported onset <or=2 h after vaccination, 27% experienced symptoms for >48 h, and 42% considered the symptoms to be severe. The surveillance case definition for ORS for 2001-2002 was revised to include onset <or=24 h after vaccination, with no restriction on duration. ORS should be incorporated into annual influenza vaccine safety monitoring.