Objective: This study aimed to determine the demographical and clinical characteristics of patients followed with severe acute respiratory illness (SARI) during 2015-2016 influenza season. Methods: Patients followed with a diagnosis of SARI between 15 December, 2015 and 22 May, 2016 were included in the study. The patients were evaluated for demographic and clinical characteristics. Respiratory tract multiplex polymerase chain reaction (PCR) test was performed for all patients' nasopharyngeal smear samples. Results: A total of 107 patients were included in the study. Of the patients, 69 (64.5%) were male, and median age was 68 (range, 0-95) years. Mean duration of complaints before admission was 3.8 days. Mean hospitalization time was 11.7 days, and 23.4% of patients were followed in intensive care unit. Most frequent admissions were between second and seventh weeks of 2016. Viral agents were found in 41(38.3%) patients in respiratory tract multiplex polymerase chain reaction (PCR) test. Of the agents, 80.5% were influenza A virus (63.4% H1N1, 7.3% H3N2, 9.7% influenza A), 14.6% were influenza B virus, 2.4% were coronavirus OC43, and 2.4% were human metapneumovirus. Crude mortality was 15.9%, SARI-specific mortality was 8.4%, influenza A (H1N1)-related mortality was 11.5%. There were no significant differences for underlying diseases and laboratory findings other than presence of chronic obstructive pulmonary disease, and elevated alanine and aspartate aminotransferase levels. Admission to intensive care unit and mortality were similar for both groups. When patients were evaluated according to the duration of complaints prior to admission, PCR positivity, necessity for intensive care unit admission and mortality were not found to be significantly different between patients with ≤4 Özet Amaç: Bu çalışmada 2015-2016 influenza sezonunda hastanemizde ağır akut solunum yolu hastalığı (SARI) tanısıyla takip edilen hastaların demografik ve klinik özelliklerinin ve bölge-mizde baskın virus suşlarının belirlenmesi amaçlandı. Yöntemler: Hastanemizde 15 Aralık 2015-22 Mayıs 2016 tarihleri arasında SARI tanısıyla izlenen hastalar çalışmaya dahil edildi. Hastaların demografik ve klinik özellikleri değerlendirmeye alındı. Tüm hastaların nazofaringeal sürüntü örnekleri, solunum yolu multipleks polimeraz zincir reaksiyonu (PCR) testiyle incelendi. Bulgular: Çalışmaya 107 hasta dahil edildi. Hastaların 69 (%64.5)'u erkek, ortanca yaş 68 (20-95 arasında) idi. Başvuru ön-cesi şikayet süresi ortalama 3.8 gün olarak bulundu. Ortalama yatış süresi 11.7 gün olan hasta grubumuzda, hastaların %23.4'ü yoğun bakım ünitesinde takip edildi. En sık başvuru 2016 yılının ikinci ve yedinci haftaları arasında oldu. Solunum yolu multipleks polimeraz zincir reaksiyonu (PCR) testinde 41 (%38.3) hastada viral etken saptandı. Etkenlerin %80.5'i influenza A virusu (%63.4 H1N1, %7.3 H3N2, %9.7 influenza A), %14.6'sı influenza B virusu, %2.4'ü koronavirus OC43 ve %2.4'ü insan metapnömovirus idi. Kaba mortalite %15.9, SARI'ye bağlı mortalite %8.4...