The new swine-origin influenza A (H1N1) strain (S-OIV) pandemia may expose immunodepressed cancer patients under chemotherapy to an increased risk of mortality. Here, we put into perspective available antiviral treatments and influenza vaccination efficacy in cancer patients and consider that recommendations for seasonal influenza vaccination for these patients are applicable for the upcoming S-OIV vaccines. We recommend a triple vaccination in cancer patients (seasonal influenza, S-OIV, streptococus pneumoniae), if possible at least two weeks before beginning chemotherapy. In case of an influenza-like illness under chemotherapy, the care will depend on the neutrophilic level. If neutrophil count is under 500 units/mm3, hospital admission is recommended with adapted isolation measures and the prescription of an antiviral treatment with oseltamivir 75 mg twice a day for 5 days, if the onset of symptoms occurred within 48 hours. In case of a sign of severity, antiviral treatment should be started regardless of time of the onset of symptoms. Probabilistic antibiotics should also be introduced. In the absence of neutropenia, home care should be favored, by explaining recommended hygienic measures and by starting an antiviral treatment with the same modalities as described previously. Hospital admission is indicated if a sign of severity is present. Patients under chemotherapy, if not vaccinated, who have had a contact with an infected person should receive a prophylactic antiviral treatment with oseltamivir 75 mg once a day for 10 days.