Four cases of essential mixed IgG-IgM cryoglobulinemia with neurologic manifestations are recorded. In one case peripheral neuropathy and recurrent cerebral symptoms were detected, and the postmortem showed diffuse encephalomalacia and multiple cerebrovascular occlusions. Findings in the other cases included myelopathy and signs of neuropathy and encephalopathy in one patient, vascular brainstern syndrome and peripheral neuropathy in another, and acute cerebrovascular ischemic stroke and repeated confusional states in the remaining patient. Systemic manifestations included cutaneous symptoms, peripheral vascular disease, arthritis, and chronic liver disease with terminal glomerulonephritis in two cases. The possible role of the cryoglobulins in the causation of the nervous system pathology is discussed.