In 66 patients (37 male/29 female, median age 51 years) with CML in stable phase the initial smears of the peripheral blood were evaluated in regard to survival. Differential count was performed on 500 nucleated cells by two investigators working independently and blind. Scrutinized statistical analysis revealed not only the well-known predictive value of the number of myeloblasts, but also a significant prognostic impact for the percentages of polymorpho-nuclear granulocytes, eosinophils and basophils.