Although Influenza vaccination is recommended for healthcare workers, vaccination rates in UK healthcare workers are only around 50%. We investigated the association between NHS sickness absence rates (using data from Health and Social Care Information Centre quarterly reports), staff vaccination rates and influenza vaccine efficacy (from Public Health England), influenza deaths (from the Office of National Statistics) and staff satisfaction (from www.NHSstaffsurveys.com). Data from 223 healthcare trusts covered approximately 800,000 staff in each of four influenza seasons from 2011; overall staff sickness rate was roughly 4.5%. Annual vaccination rates varied between 44% and 54%. Higher NHS trust vaccination rates were associated with reduced sickness absence (β = –0.425 [95% CI –0.658 to –0.192], p<0.001). Thus, a 10% increase in vaccination rate would be associated with a 10% fall in sickness absence rate. Influenza vaccination for NHS staff is associated with reduced sickness absence rates.