ObjectiveThis study investigates the distribution of the workforce of one large National Health Service (NHS) employer in relation to socioeconomic deprivation and how sickness absence rates varied across these levels of deprivation.DesignShare of the working age population that was employed at the NHS organisation mapped by area deprivation. The study used negative binomial regression models to investigate the extent to which wage level, occupational group and area deprivation were associated with sickness absence among employees.SettingThe study used electronic staff records (2018–2019) of a large NHS organisation in the North West of England.ResultsIn the most deprived areas, an additional person per 1000 working age population were employed at this NHS organisation compared with the most affluent areas. Employees from the most deprived quintile had 1.41 (95% CI 1.16 to 1.70) times the higher sickness rates than the employees from the least deprived quintile, when adjusting for age and sex. These differences were largely explained by differences in wage levels and occupation groups, with the lowest wage employees having 2.5 (95% CI 1.87 to 3.42) times the sickness absence rate as the highest wage group and the nursing and midwifery employees having 1.8 (95% CI 1.50 to 2.24) times the sickness absence rate as the administrative and clerical group.ConclusionThis large NHS organisation employed people disproportionately from deprived areas. They were considerably more likely to experience sickness absence compared with people from affluent areas. This appears to be because they were more likely to be in lower wage employment and employed in nursing and nursing assistant. Workplace health policies need to target these workers, adapting to their needs while enabling improvements in their working conditions, pay and career progression.