Hematopoietic cytokines have been implicated in the pathogenesis of malignant diseases. This study compared the diagnostic utility of hematopoietic growth factors with commonly accepted tumor marker (CA 125) in the early stages (I and II) of endometrial cancer (EC) patients (65) in relation to the control groups: uterine myoma patients (40) and healthy subjects (45). The pretreatment plasma levels of interleukin 3, stem cell factor, granulocyte-macrophage-colony stimulating factor, granulocyte-colony stimulating factor, and macrophage-colony stimulating factor (M-CSF) were determined by the use of immunoenzyme assay, and those of CA 125 were determined by chemiluminescent microparticle immunoassay. Our results have demonstrated significant differences in the concentration of cytokines and CA 125 between the groups of EC patients, uterine myoma patients, and the healthy controls. M-CSF has demonstrated equal to CA 125 or higher values of the diagnostic sensitivity, the predictive values of positive and negative test results, and the area under the receiver-operating characteristics curve in the tested groups. These findings suggest the usefulness of M-CSF in the diagnosis of EC and uterine myomas.