Abstract In the Netherlands, occupational physicians can diagnose burnout when employees report sick. Their guideline distinguishes between stress complaints lasting < 3 months, adaptation disorder with complaints lasting 3-6 months and burnout with complaints lasting > 6 months at moment of diagnosis. The Four-Dimensional Symptom Questionnaire (4DSQ) is recommended to assess and monitor. The new Burnout Assessment Tool (BAT) might be an alternative. Research questions were: 1) What are the sickness absence duration, 4DSQ and BAT-scores of absentees diagnosed with stress complaints, adaptation disorder and burnout?; 2) Is the BAT a better predictor of sickness absence duration than the 4DSQ? From 2020-2023, data was collected among all 3,462 employees who were absent due to stress complaints, adaptation disorder or burnout at one large occupational health and safety service via registry data and an employee questionnaire. Results show that two-thirds of those with stress complaints, half of them with adaptation disorder and one third with burnout were absent for less than half a year. 4DSQ and BAT scores differed significantly between the three groups (p<.05). The BAT explained 0.8% of variance in absence duration (p< .001) when controlled for covariates, which explained 1.6% of variance (p< .001). The explanation by BAT was 1.9% within the group with stress complaints (p = 0.002), .4% within the group with adaptation disorder (p=.022) and absent within the group with burnout. Comparable results were found for the 4DSQ. The differences in absence duration between the three groups aligned with the Dutch guidelines. The BAT nor the 4DSQ were clinically relevant predictors of duration of absence for stress-related diagnoses among absentees in the Netherlands. To reduce productivity loss, it seems better to report sick when still in the stage of stress complaints than to wait until a full burnout has developed. The BAT and 4DSQ might help risk assessment in the working population. Key messages • The sickness absence duration of Dutch employees diagnosed with burnout is much longer than that of those with adaptation disorder or stress complaints. • Both the instrument recommended in the guideline and the new instrument have no clinical relevance in predicting sickness absence duration of stress-related diagnoses.