Background--Limited data are available on return to work and subsequent detachment from employment after admission for myocardial infarction (MI). Methods and Results--Using individual-level linkage of data from nationwide registries, we identified patients of working age (30-65 years) discharged after first-time MI in the period 1997 to 2012, who were employed before admission. To assess the cumulative incidence of return to work and detachment from employment, the Aalen Johansen estimator was used. Incidences were compared with population controls matched on age and sex. Logistic regression was applied to estimate odds ratios for associations between detachment from employment and age, sex, comorbidities, income, and education level. Of 39 296 patients of working age discharged after first-time MI, 22 394 (56.9%) were employed before admission. Within 1 year 91.1% (95% confidence interval [CI], 90.7%-91.5%) of subjects had returned to work, but 1 year after their return 24.2% (95% CI, 23.6%-24.8%) were detached from employment and received social benefits. Detachment rates were highest in patients aged 60 to 65 and 30 to 39 years, and significantly higher in patients with MI compared with population controls. Predictors of detachment were heart failure (odds ratio 1.20 [95% CI, 1.08-1.34]), diabetes mellitus (odds ratio 1.13 [95% CI, 1.01-1.25]), and depression (odds ratio 1.77 [95% CI, 1.55-2.01]). High education level and high income favored continued employment. Conclusions--Despite that most patients returned to work after first-time MI, about 1 in 4 was detached from employment after 1 year. Several factors including age and lower socioeconomic status were associated with risk of detachment from employment.