Introduction. Since the introduction of first measures designed to tame the COVID-19 pandemic, several speculations have been made about their simultaneous effect on seasonal influenza. Although social distancing policies could be effective in mitigating influenza spread, the ultimate consequences remain unknown. Aim of this study is to evaluate the effect of COVID-19 pandemic on influenza related-pneumonia in hospitalized patients. Methods. We conducted a cross-sectional retrospective analysis to evaluate the rate of influenza-related pneumonia in current pandemic year (April 2020 to March 2021), compared to previous five years (April 2015 to March 2020). Analysis was based on the clinical records and ICD-9 diagnosis code of all adult patients admitted for pneumonia at Fondazione Policlinico Universitario A. Gemelli, IRCCS of Rome. The diagnosis of pneumonia caused by influenza and by other common respiratory tract viral infections were assessed. Results. Overall 15,029 (15.2%) hospitalized for pneumonia were considered. Patients’ median age was 76 years [interquartile range 64 – 84); males were 8652 (57.6%). Influenza-related pneumonia almost disappeared in the 2020-2021 (0.0002%) compared previous five years (1.5%). Conversely, other virus related pneumonia had a similar incidence in both the evaluated periods. Discussion The present analysis suggests that during COVID-19 pandemic the cases influenza-related pneumonia was basically absent among our hospitalized patients. Interestingly, other virus-related pneumonia showed a countertrend, and the actual incidence rate was slightly higher than previous five years. Further investigations are needed to assess the ultimate effect of COVID-19 pandemic on the total trend of influenza and other respiratory tract infections.