Systemic lupus erythematosus (SLE) patients are at high risk of developing osteonecrosis, as they require corticosteroid therapy for life. The purpose of this study was to use periodic MRI analysis to clarify (1) the incidence of new osteonecrosis associated with long-term corticosteroid therapy in SLE patients, and (2) the risk factors for delayed osteonecrosis in SLE patients. We prospectively studied 291 joints (134 hips and 157 knees) in 106 SLE patients without osteonecrosis after initial corticosteroid therapy, with a mean follow-up period of 13.6 years and a follow-up rate of 71%. All patients had undergone periodic MRI examination of the hip and knee joints for >10 years. New osteonecrosis developed in 6 joints (3%) and only occurred after SLE recurrence in association with increased corticosteroid doses (to>30 mg/day [p=0.008]). New lesions were delayed for a mean 5.9 years after initial corticosteroid administration. The mean time from SLE recurrence to appearance of new lesions was 6.2 months. SLE recurrence occurred in 131 joints (45%), while SLE was well controlled in 160 joints (55%). We suggest that with respect to long-term effects, total cumulative dose and duration of corticosteroid therapy do not contribute to osteonecrosis. However, SLE recurrence is a risk factor for new osteonecrosis. We recommend MRI screening for osteonecrosis at SLE recurrence.