Abstract This study analyzes supply characteristics and factors associated with the treatment of rheumatoid arthritis in Brazil, with a focus on disease course-modifying biological drugs (bioDMARDs). A retrospective study was conducted with secondary data from the Outpatient Information System of the Unified Health System. Patients aged 16 years or older who were treated in 2019 were eligible. The analyses were performed with exposure factors in relation to the outcomes: bioDMARD use and population size. The study included 155,679 patients, 84.6% of whom were women. There was a greater exchange of bioDMARDs and a greater supply of rheumatologists in the larger municipalities (more than 500,000 inhabitants). Almost 40% of the patients used bioDMARDs, and they showed greater adherence to treatment (57.0% versus 64%, p=0.001). The dispensing of bioDMARDs occurred in more than one-third of the patients treated for rheumatoid arthritis (RA) in Brazil and was associated with a higher percentage of availability of rheumatologists and larger population size.