Background: Febrile neutropenia is one of the most feared complications in actively treated patients in oncology clinics. The impact of H1N1 infection on the management of the febrile neutropenia in endemic areas, especially if the patient is presented with pulmonary symptoms, is not clear. Case report: A Forty seven year old male patient diagnosed with mantle cell lymphoma, admitted to our center with neutropenic fever 8 days after chemotherapy. The patient revealed classical symptoms of influenza like headache and myalgia and also had rhonchus and cough supporting lower respiratory tract infection. He was finally diagnosed as influenza A (H1N1) infection. Conclusion: Influenza infection is an important etiological agent in immunocompromised hosts, namely neutropenic patients, which cause significant morbidity and mortality. Viral etiology and antiviral treatment should also be considered in suspected patients especially during epidemics and pandemics.