OBJECTIVE To screen potential adverse drug event （ADE） signals for the treatment of multiple sclerosis （MS） with ofatumumab， and to provide reference for the safe use of drugs in clinical practice. METHODS Using “ofatumumab” and the trade name “Kesimpta” as the search keywords， adverse event （AE） reports related to ofatumumab included in FDA Adverse Event Reporting System database from January 2009 to December 2023 were screened， and their reason contained the “multiple sclerosis”； ADE signal mining and analysis were conducted by reporting odds ratio method and proportional reporting ratio method. RESULTS A total of 21 759 eligible AE reports were selected， involving 62 449 AE cases； 27 system organ classes included general diseases and various reactions at the site of administration （15 021 cases）， neurological diseases （9 668 cases）， infectious and invasive diseases （5 967 cases）， injury， poisoning and surgical complications （4 952 cases）， musculoskeletal and connective tissue disorders （4 647 cases）. A total of 21 759 AE reports correspond to 606 ADE signals， including 234 ADE positive signals. A total of 107 ADE positive signals were not included in drug instruction of ofatumumab， including flu-like diseases， nasopharyngitis， cough， urinary tract infection， sore throat， insomnia， runny nose， anemia， hair loss， atrial fibrillation， and thrombocytopenia， etc. CONCLUSIONS In the process of using ofatumumab for MS， sufficient attention should be paid to ADE included in drug instructions. The ADE with strong signal strength screened in this study should also be paid special attention to， such as flu-like diseases， hemocytopenia， temperature intolerance， optic neuritis， and moyamoya disease. The increased risk of infection， cardiovascular disease， and potential damage to the respiratory and spiritual systems caused by ofatumumab can not be ignored.