A 43-year-old Japanese woman was referred to our hospital in 1997 because of Raynaud's phenomenon. Systemic lupus erythematosus was diagnosed on the basis of the presence of antinuclear antibody (1:1,280), anti-DNA antibody (1:640), anti-Sm antibody, antiphospholipid antibody, lymphopenia, and proteinuria. She developed pulmonary fibrosis in 1999 and pulmonary hypertension in 2001. In October 2002, a 24-hr continuous infusion of epoprostenol was started. Dyspnea, Raynaud's phenomenon, and pulmonary hypertension improved with low-dose epoprostenol (3.0 to 4.0 ng kg(-1) min(-1)). The patient could not tolerate larger doses of epoprostenol so 4.0 ng kg(-1) min(-1) was selected as the maintenance dose. The clinical course was uneventful at this dosage. It appears that pulmonary hypertension can be controlled with low-dose epoprostenol such as 3.0 to 4.0 ng kg(-1) min(-1) in some rheumatic patients.