Hantavirus pulmonary syndrome is a disease caused by the inhalation of excreta from infected deer mice. In Canada, the majority of hantavirus pulmonary syndrome cases occur in the western provinces of British Columbia, Alberta, Saskatchewan and Manitoba and the primary cause of the illness is the Sin Nombre virus. Only one case of hantavirus pulmonary syndrome has been documented in eastern Canada (Québec); however, Sin Nombre virus-infected deer mice have been identified across the country. Although cases are rare (yearly case numbers range from zero to 13 and the total number of confirmed cases in Canada now total 109), the mortality rate among infected individuals is approximately 30%. The majority of cases occur in the spring and early summer indicating seasonally-associated risk factors for viral exposure. In 2013 and 2014, a substantial increase in the number of hantavirus pulmonary syndrome cases was identified; however the cause remains unclear. No antivirals or vaccines are currently available and treatment is supportive. Public education, rodent control and the use of personal protective measures are key to avoid infections in at-risk populations.