The aim of this study was to prospectively evaluate the efficacy and safety of tacrolimus (TAC) in various manifestations of systemic lupus erythematosus (SLE) patients in daily clinical practice. Each of the 21 TAC-treated patients with SLE in our care over 2 years was enrolled in this open-label trial. Patients were administered TAC at a dosage of 1-6 mg once daily, followed up for 24 weeks. Efficacy and safety were evaluated utilizing clinical and laboratory findings. As treatment targets, TAC was preferentially used with oral corticosteroid administration for mild active manifestations such as arthritis, skin eruptions, or asymptomatic nephritis. In efficacy, the mean value of the SLE disease activity index was significantly reduced to 4.1, 2.7, 1.8, and 1.2 (N=21, 20, 16 and 13) at 0, 4, 12, and 24 weeks, respectively. In eight cases, treatment was discontinued within 24 weeks due to insufficient effects (6 cases) and side effects (2 cases). Non-serious side effects were observed in only five cases (23.8%) over 24 weeks. TAC can be considered both effective and safe for the treatment of various manifestations of SLE.