Patients with hematologic disease are likely to be at increased risk for infection with influenza. We retrospectively analyzed 11 cases of patients with hematologic disease who were infected with pandemic H1N1 virus in our department, including their clinical manifestations, laboratory and imaging findings, outcomes of antiviral therapy, and factors associated with mortality. Notably, nine patients had lower respiratory tract disease. Five patients progressed to respiratory failure and eventually died, despite treatment with antivirals and/or corticosteroids and/or mechanical ventilation. We concluded that H1N1 2009 infection was associated with a severe course and high rate of mortality in patients with hematologic disease, and early diagnosis and antiviral treatment were important to reduce the rate of severe complications and mortality.