Bleeding disorders are commonly associated with hemato-oncologic diseases. We report a 68 years old male with a chronic myelomonocytic leukemia derived from a long lasting mielodysplastic syndrome that did not respond to treatment with Azacitidine. The patient was hospitalized due to tonic clonic seizures. A CAT scan showed a hematoma in the frontal lobe. A new assessment of hemostasis revealed an isolated deficiency of Factor X. We speculate that this deficit could be secondary to consumption due to the chronic Myelomonocytic Leukemia.