Introduction: In oncological patients influenza may result in severe forms associated with high mortality (11-33% in solid cancers, 23% in bone marrow transplant), one of them being acute respiratory distress syndrome (ARDS). Objective: Evaluation of diagnostic, management and outcome particularities in ARDS AH1N1 influenza oncological patients. Material and methods: The study enrolled all ARDS AH1N1 influenza patients, diagnosed and managed in ICU IRO Iași in January-February 2018 during a hospital-acquired influenza outbreak. Analyzed parameters were patient related (cancer type and treatment), influenza related (virus type and identification tests), ARDS related (severity, management, outcome). Results: Out of 40 symptomatic or influenza contact asymptomatic patients, 21 tested positive for AH1N1 influenza virus, 9 out of them having ARDS managed in ICU. 5 pts presented severe ARDS in the context of post-therapeutic severe immune compromise: 4 pts post-chemotherapy medullary aplasia for hemato-oncological disease and 1 pt post-radio/chemo/surgical therapy for gynecological cancer. All received ventilatory support: 3 pts invasive ventilatory support in prone position (worst PaO2/FiO2 29-46 mmHg, nonsurvivors), 2 pts non-invasive ventilatory support (worst PaO2/FiO2 54-94 mmHg, survivors). After 25th Jan 2018 (first case) epidemiological alert and management were instituted, resulting in outbreak control on 23rd Feb 2018 (last case). Conclusions: In immuno-compromised oncological patients AH1N1 influenza may rapidly generate a hospital-acquired outbreak and severe ARDS forms associated with high mortality. Early diagnostic and management are the most effective strategies in reducing associated mortality and controlling influenza outbreak.