This article analyses the relationship between employee collective voice, measured by union density and institutionalized forms of employee representation at enterprise level, and short-term sickness absence rates in 24 European countries over the period 1996–2010. It relies on individual-level data on sickness absence from the European Labour Force Survey combined with country-level data on employee collective voice. There is a small but significant and non-trivial, negative relationship between employee collective voice and short-term sickness absence. Regression analysis suggests that if union density had remained at the 1996 level, short-term sickness absence would have been, on average, 2.5 hours lower per year than in 2010.