The objective of this study was to assess the usefulness of tacrolimus (TAC) for rheumatoid arthritis (RA) patients. The first 101 consecutive RA patients in whom TAC treatment was initiated were prospectively registered and their data analyzed. Clinical variables were extracted from the Institute of Rheumatology, Rheumatoid Arthritis (IORRA) database. The 101 patients included 85 females and 16 males. Average doses of TAC were 1.62 mg/day at entry and 2.13 mg/day at month 12. The average doses of concomitantly prescribed prednisolone (6.92 mg/day) and methotrexate (MTX; 8.59 mg/week) were higher than those in all RA patients in the IORRA cohort. At month 12, 57 patients remained on TAC therapy; 18 patients had discontinued TAC due to side effects, and 16 patients had discontinued due to inefficacy. Adverse reactions responsible for discontinuation included gastrointestinal symptoms, renal dysfunction, and infection. According to the European League Against Rheumatism (EULAR) response criteria, 56.5% of the patients who continued TAC at 12 months experienced "good" or "moderate" responses. Through the use of last observation carried forward (LOCF) methodology, the average Disease Activity Score (DAS) 28 significantly improved. We confirmed the usefulness of TAC for the treatment of RA and found that TAC is suitable for RA patients who are unable to use biologic agents or to tolerate a high dose of MTX because of their complications or background factors.