This occupational biomonitoring guidance document was elaborated in a joint activity including more than 40 institutes and organisations in collaboration with the OECD.The guidance document presents current approaches used to derive biomonitoring values and provides globally harmonized recommendations on how-to derive and apply occupational biomonitoring assessment values. The derived healthbased human biomarker assessment values are referred to as Occupational Biomonitoring Levels (OBLs). OBLs are suitable for the use in exposure assessment and screening a level of health-risk and finally, workplace risk management. Moreover, we strengthen the option of deriving Provisional Occupational Biomonitoring Levels (POBLs) for chemical substances with limited human toxicity data availability, which can be used for identifying and managing possible occupational health-risks.