The clinical outcomes of acute promyelocytic leukemia (APL) have improved greatly, but treatment failure still occurs. Identification of patients with poor prognosis is fundamental, and we propose a new clinical prognostic system (CBC-score) consisting of WBC, platelet count, and hemoglobin level. Between 1995 and 2009, 156 patients with APL from seven institutes in Korea were retrospectively reviewed. In the new CBC-score system, each of the following (WBC ≥ 10 × 109/L, platelet <40 × 109/L, hemoglobin <8.0 g/dL) was considered as a risk factor; the sum of each was designated as the CBC-score. With a median follow-up of 8.4 years, the complete remission (CR) rate was 81.4 % (127/156), while 24 (15.4 %) were considered as treatment failures due to early death (ED). The 5-year overall survival (OS), leukemia-free survival, and cumulative incidence of relapse were 73.8, 82.8, and 13.5 %, respectively. Compared to the individual CBC parameters, combined prognostic systems such as PETHEMA or CBC-score provided better prognostic stratification. Compared to PETHEMA stratification, the proposed prognostic CBC-score system showed better stratification of APL patients in terms of CR rates (p = 0.004), OS (p = 0.004), and ED (p = 0.008). This retrospective study suggests that the proposed CBC-score may provide better prognostic stratification of APL patients.