The morbidity and mortality of the 2014-2015 influenza season were more important than those in previous years. We assessed the impact of the 2014-2015 influenza season on the length of stay (LOS) and workload in an academic emergency department (ED). This is a monocentric retrospective study. The database of the microbiology laboratory was used to identify influenza nasal swabs performed during the influenza seasons from 2010 to 2015. Patients admitted to the ED during these periods were identified through the administrative database and cross-checked with patients who underwent an influenza nasal swab in the ED. Median LOS was used to estimate the impact of the isolation procedures on ED LOS. Bed occupancy rate and mean LOS in the ED were calculated as proxy of the ED workload. During the 2014-2015 influenza season, 55.9% of ED patients (n = 123) with confirmed influenza were hospitalised. In terms of workload, despite that influenza patients represented only 2.2% of all ED patients during the season, they occupied 28% of ED beds with respiratory isolation during the delay to realise and obtain the test results, as well as during the delay before being discharged home or transferred to a hospital ward. The median ED LOS for influenza-confirmed patients was significantly longer in comparison with all ED patients (21.6 h vs 4.0 for ambulatory patients and 24.7 h vs 12.3 for hospitalised patients). The 2014-2015 influenza season had significant consequences in terms of ED LOS and bed use. It dramatically increased the workload in the ED.