Systemic lupus erythematosus (SLE) is a chronic multisystemic inflammatory autoimmune disease. Hematologic abnormality is more frequent and the frequency of using high dose steroid and immunosuppressant as treatment is higher in children, because the number of involved major organ is numerous and the disease progress is often rapid in the SLE of children. We reported an experience of lupus nephritis flare after tapering the steroid in 9 years old boy who was diagnosed focal proliferative glomerulonephritis.