Introduction: Although the burden of adverse drug reactions (ADRs) has a significant impact on patients’ quality of life, thorough knowledge about patients’ perspectives on the burden of ADRs attributed to biologics is lacking. Objectives: This study was conducted to gain insight into the patient burden of ADRs experienced with biologic use. Methods: The Dutch Biologic Monitor is a prospective, multicentre, event monitoring cohort system including information collected by web-based questionnaires from patients using biologics, mainly for immune-mediated inflammatory diseases (IMIDs). Patients were asked to complete bimonthly questionnaires on biologics used, indication for the biologic, experienced ADRs, consequences of ADRs and burden on a...