OBJECTIVE: To assess differences in mortality rates between social security statuses in two independent samples of Belgian and Spanish male workers. METHODS: Study of two retrospective cohorts (Belgium, n=23,607; Spain, n=44,385) of 50-60 year old male employees with 4 years of follow-up. Mortality rate ratios (MRR) were estimated using Poisson regression models. RESULTS: Mortality for subjects with permanent disability was higher than for the employed, for both Belgium [MRR=4.56 (95% CI: 2.88-7.21)] and Spain [MRR=7.15 (95% CI: 5.37-9.51)]. For the unemployed/early retirees, mortality was higher in Spain [MRR=1.64 (95% CI: 1.24-2.17)] than in Belgium [MRR=0.88 (95% CI: 0.46-1.71)]. CONCLUSION: MRR differences between Belgium and Spain for unemployed workers could be partly explained because of differences between the two social security systems. Future studies should further explore mortality differences between countries with different social security systems. ; This work was supported by grants from the Instituto Salud Carlos III-FEDER (FIS PI14/00057), the Spanish National Health Institute Carlos III (FIS 08/0914 and FIS 11/01470), the CIBER of Epidemiology and Public Health and the Research Foundation Flanders (G036816N).