We describe Influenza A/pandemic 2009/H1N1 in two allogeneic hematopoietic cell transplantation recipients. The main presentation in both cases consisted of flu-like symptoms manifesting as, fever, arthralgias and myalgias. The virus was isolated in one case from a throat swab and in another case following a bronchoalveolar lavage. Both patients received oseltamivir at a dose of 75 mg orally twice day. The dose of oseltamivir was increased to 150 mg twice per day due to the lack of improvement or progression of symptoms. In one case, clinical symptoms resolved without sequelae. In the second case, pulmonary symptomatology continued to deteriorate, despite aggressive polymicrobial treatment, requiring mechanical ventilation and ultimately the patient died from respiratory failure. These cases highlight the potentially serious effect of the ongoing Influenza A/pandemic 2009/H1N1 pandemic in this very vulnerable population and the urgent need to establish emergency preparedness strategies by oncology and bone marrow transplantation staff to face this serious healthcare challenge.