We have determined the main hemorheological parameters in a group of patients suffering from myotonic dystrophy and in another group with oculopharyngeal or limb-girdle myopathy. From the results we have obtained it is evident that of all the rheological parameters considered only hematocrit, fibrinogen and fibrinogen/albumin ratio are different in patients with myotonic dystrophy when compared to that of normal controls. There were no variations in blood, plasma and serum viscosities and in erythrocyte filterability. In addition, hemorheological alterations were not present in patients with oculopharyngeal or limb-girdle myopathy.