Objective: To determine the incidence of influenza vaccination among homeless individuals with mental illness in Toronto. Methods: A retrospective chart review was carried out using a random sample of homeless individuals with mental illness who were participants of the At Home/Chez Soi Study. Primary care charts were obtained and reviewed for the incidence influenza vaccination within a 1-year period. Results: Of the 75 participants for whom charts were reviewed, 5 (6.7%) had documentation indicating receipt of the influenza vaccination in the year prior to study recruitment. Conclusion: This study raises awareness of the low incidence of homeless adults receiving the influenza vaccination in Toronto. The data are concerning given the high risk of morbidity from communicable respiratory illnesses in this group. Further research into the causes of low influenza vaccination rates among homeless Canadians is needed to develop strategies for increased delivery of the vaccination.