This interim analysis of postmarketing surveillance data for adalimumab-treated rheumatoid arthritis (RA) patients summarizes safety and effectiveness during the first 24 weeks of therapy for the first 3,000 patients treated in Japan (June 2008-December 2009). Patient eligibility for antitumor necrosis factor therapy was based on the Japanese College of Rheumatology treatment guidelines and Japanese labeling. All patients were screened for tuberculosis. Approximately 50% of the population was biologic naïve, 66% received concomitant methotrexate (MTX), and 72% received concomitant glucocorticoids. The overall incidence rate of adverse events was 31% (5.5% serious) and that of adverse drug reactions (ADRs) was 27% (4.1% serious). Incidence rates of ADRs and serious ADRs were similar regardless of prior biologic therapy or concomitant MTX use but were significantly higher in patients receiving glucocorticoids compared with those not receiving glucocorticoids. Bacterial/bronchial pneumonia occurred in 1.2% of patients; interstitial pneumonia, 0.6%; Pneumocystis jirovecii pneumonia, 0.3%; tuberculosis, 0.13%; and administration-site reactions, 6.1%. Mean 28-joint Disease Activity Scores decreased significantly after 24 weeks from 5.29 to 3.91. All subgroups showed significant improvement, particularly the biologic-naïve patients receiving concomitant MTX. No new safety concerns were identified. ADR Incidence rates were similar to those of other biologic agents approved for RA.