It is unclear when occupational health providers should re-evaluate workers after mental healthrelated absences from work. Aims: To investigate the time to recurrence of mental health-related absences, stratified by International Classification of Diseases-Tenth Revision (ICD-10) diagnostic categories. Methods: A 10-year observational study of workers employed at a steel mill. Sickness absence data were retrieved from an occupational health register. Mental health-related absences were defined as absence due to emotional disturbance or mental and behavioural disorders. The first mental healthrelated absence since baseline was called the index episode. Recurrences were defined as mental health-related absences occurring >28 days after recovery from the index episode. The frequency of recurrent mental health-related absence was assessed by the recurrence density (RD) per 1000 person-years. The time to recurrent mental health-related absence was investigated by Kaplan-Meier survival analysis. Results: Of 15 461 workers, 391 had recurrent mental health-related absences. RD was 30.5, 34.3, 29.9 and 37.7 per 1000 person-years after index episodes due to emotional disturbance, mood disorders, neurotic disorders and other psychiatric disorders, respectively. RDs did not differ across ICD-10 diagnostic categories. The median time to recurrent mental health-related absence was 15.2 months [95% confidence interval (CI) 12.6-17.7] and was shortest for mood disorders (5.2, 95% CI 1.4- 8.9 months) and specific psychiatric disorders (5.3, 95% CI 1.0-13.1 months). Conclusions: Based on this observational study, we suggest that occupational and primary health care providers consider reviewing the mental health status of workers 6 months after recovery from mental healthrelated absence.