Objective Changes in the global economy have produced new types of employment that enable the flexibilization of work and the creation of temporary contracts, which tend to promote unstable work. Several studies have found that unemployment and job insecurity are associated with an increase in morbidity and mortality. Our objective is to study the association between labour trajectories and mortality.

Methods We conducted a nested case-control study derived from the Spanish WORKing life Social Security (WORKss) cohort study. The WORKss cohort, initiated in 2004, is based on administrative registries from the Social Security system in Spain and contains work information dating back to 1981. Cases and controls were selected by incidence-density sampling and matched by sex and age. Cases consisted of all deaths occurring during the 2004–2013 period and controls consisted of individuals alive at time the case occurred.

Results During 2004–2013, 11,439 women and 42,550 men died. After controls were matched, the sample consisted of 107,978 individuals. We had access to at least 10 years of information during the work age of all individuals (ages 16–65). Mortality was associated with uptake of permanent disability pension and less time spent in employment during working age. In men, more periods of inactivity were associated with mortality.

Conclusions Unstable labour trajectories characterised by less time spent in employment and more periods of inactivity are associated with mortality. Uptake of permanent disability pension is associated to mortality.