Objective: To evaluate treatment patterns and healthcare resource utilization (HCRU) after initiating biologic disease-modifying antirheumatic drugs (bDMARDs) in Korean patients with rheumatoid arthritis (RA). Methods: Patients newly diagnosed with RA in 2014 were identified and followed up on using the Korean National Health Insurance Database until 2018. The initial line of therapy (LOT) or LOT1 included patients treated with conventional DMARDs (cDMARD). Patients who started a bDMARD were assigned to LOT2 bDMARD. Those who moved from a bDMARD to a Janus kinase inhibitor were assigned to LOT3. Analyzed outcomes were treatment patterns and HCRU in LOT2 bDMARD. Results: The most prescribed initial bDMARD was a tumor necrosis factor inhibitor. Seventy-five percent of patients had changes in treatment after starting a bDMARD, such as addition/removal or switch of a DMARD, and transition to LOT3. For the first and second changes in LOT2 bDMARD, adding a cDMARD to a bDMARD was more common than switching to another bDMARD (7.98% vs. 2.93% for the first change, and 17.10% vs. 6.51% for the second change). Tocilizumab was the most common bDMARD that was switched to. Forty-eight percent of patients had at least one hospitalization after initiating bDMARDs. Of these patients, 64.3% were admitted due to RA-related reasons. Conclusion This real-world study provides information on treatment characteristics of RA patients in Korea after starting a bDMARD. In contrary to guidelines, cDMARD addition was more often than bDMARD switches in daily clinical practice.