Introduction: Influenza is a serious infectious disease causing mortality and morbidity. The aim of our study was to describe the incidence, seasonal distribution and clinical characteristics of influenza cases in 2017-2018 winter months and to study risk factors for increased hospital admission and complications. Methods: In this retrospective descriptive study, we included patients presenting to the pediatric emergency unit in our hospital between 1st October 2017 and 31th March 2018, who were evaluated by a pediatrician and had a positive influenza test result. Clinical characteristics of the patients were recorded and risk factors for admission and complications were studied. Results: Four hundred and twelve patients were enrolled in the study. The incidence of influenza in patients presenting to the pediatric emergency unit during the study period was 2.2%. The incidence increased between mid December and mid January. The mean age of the patients was 4.6±3.3 years. 75.7% of cases were positive for influenza A. 18% of patients had lower respiratory tract infection, 2.9% had myositis and 10.7% had cytopenia. 4.4% of patients were hospitalized. The mean length of hospital stay was 4.44±3.03 days. The frequency of hospital admission was significantly higher in patients who had fever and pre-existing medical conditions and those who were on antibiotic treatment. When time to start oseltamivir treatment increased, the risk of developing complications increased significantly. Conclusion: 2017-2018 seasonal influenza outbreak caused especially by influenza A mainly affected preschool children between mid December to mid January. Children with pre-existing medical conditions were more commonly admitted to hospital. The most common complication was lower respiratory tract infection and, increased time to start oseltamivir treatment increased likelihood of developing complications. Necessary precautions should be taken for next influenza outbreak in the light of the present information.