During the 2015–16 influenza season (October 4, 2015–May 21, 2016) in the United States, influenza activity* was lower and peaked later compared with the previous three seasons (2012–13, 2013–14, and 2014–15). Activity remained low from October 2015 until late December 2015 and peaked in mid-March 2016. During the most recent 18 influenza seasons (including this season), only two other seasons have peaked in March (2011–12 and 2005–06). Overall influenza activity was moderate this season, with a lower percentage of outpatient visits for influenza-like illness (ILI),^? lower hospitalization rates, and a lower percentage of deaths attributed to pneumonia and influenza (P&I) compared with the preceding three seasons. Influenza A(H1N1)pdm09 viruses predominated overall, but influenza A(H3N2) viruses were more commonly identified from October to early December, and influenza B viruses were more commonly identified from mid-April through mid-May. The majority of viruses characterized this season were antigenically similar to the reference viruses representing the recommended components of the 2015–16 Northern Hemisphere influenza vaccine (1). This report summarizes influenza activity in the United States during the 2015–16 influenza season (October 4, 2015–May 21, 2016)^§ and reports the vaccine virus components recommended for the 2016–17 Northern Hemisphere influenza vaccines.