OBJECTIVE: To report the clinical features of patients with systemic lupus erythematosus (SLE) associated with thrombotic thrombocytopenic purpura (TTP). Their diagnosis, treatment, and prognosis were also discussed. METHODS: A total of 25 TTP-SLE pediatric patients were included in this study. Their clinical symptoms, laboratory findings, disease activity, and renal biopsy were retrospectively reviewed. RESULTS: The median age of the patient cohort was 14 years old. Nine patients were first diagnosed with SLE, followed by the diagnosis of TTP-SLE, whereas 15 patients were diagnosed with TTP and SLE concurrently. All the 25 TTP-SLE patients had decreased platelet count and microangiopathic hemolytic anemia. Fever, rash, edema and neurological symptoms were the main clinical symptoms. Fragmentation of erythrocytes on blood smear and increased LDH were found in all patients. Nineteen patients (76%) had impaired renal function. Renal biopsy showed that most of the patients had lupus nephritis class IV (20%) and TMA (20%). 13 patients (52%) were treated with glucocorticoids in combination with immunosuppressive agent, and 10 patients (40%) were treated with plasma exchange combined with glucocorticoids plus immunosuppressive agent. One patient died due to lung infection; others had disease remission. Fifteen patients had follow-up regularly, and their conditions were stable. CONCLUSION: Patients with TTP-SLE often had moderate to severe lupus disease activity. Testing of LDH level and blood smear should be performed when kidney and neurological symptoms arise in children with SLE. The use of combination therapy, glucocorticoids plus immunosuppressive agent, provided satisfactory clinical outcome. Patients with refractory TTP-SLE will also need plasma exchange therapy.