This study was purposed to assess the efficacy of stanozolol for treatment of childhood patients with acquired non-severe aplastic anemia (NSAA). The records of 114 children with acquired NSAA treated in hospital between January 1996 and January 2009 were analyzed retrospectively. All patients received stanozolol with the dose of 0.1 mg/(kg·d). Some patients were treated with supportive care. The incidence and the risk factors of progression severe aplastic anemia (SAA) including gender, age, absolute neutrophil count, absolute reticulocyte count, dependent or independent of transfusion, the ratio of granulocytes and erythrocytes were evaluated. The results indicated that at a median follow-up of 52 months (range 5 - 181), 6 patients (5.3%) progressed into SAA, 93 (81.6%) remained in NSAA, and 15 (13.2%) had complete remission. Patients with dependent of transfusion (platelet count < 10 × 10(9)/L and/or haemoglobin < 70 g/L) have higher risk to progress into SAA (19.2% vs 1.1%) (p = 0.016); patients with lower absolute neutrophil count (ANC) (< 0.8 × 10(9)/L) or with lower absolute reticulocyte count (ARC) (< 40 × 10(9)/L) at diagnosis have higher risk to progress into SAA (8.1% vs 0%) (p = 0.029); (9.1% vs 1.7%) (p = 0.034); Those patients with lower ANC (ANC < 0.8 × 10(9)/L) and lower ARC (ARC < 40 × 10(9)/L) have higher risk into progress to SAA (19.2% vs 1.1%) (p = 0.016). It is concluded that NSAA patients treated with Stanozolol progress into SAA with the rate of 5.3%. Those patients with dependent of transfusion or ANC < 0.8 × 10(9)/L or/and ARC < 40 × 10(9)/L have higher risk of progress into SAA.