Involvement of the central nervous system (CNS) by multiple myeloma, defined by the detection of malignant plasma cells in the cerebrospinal fluid in the presence of suggestive symptoms, is considered extremely rare. We present the characteristics of 25 such patients (18 previously reported) intended to receive high-dose treatment at the University of Arkansas over the last 12 years; an extensive review of the published literature since 1968, including 71 patients, is also presented. In both patient groups, high tumor burden was overwhelmingly present while circulating plasma cells were detected in a significant proportion of cases. We also observed a strong association of CNS involvement with unfavorable cytogenetic abnormalities (especially translocations and deletion of the chromosome 13), plasmablastic morphology and additional extramedullary myeloma manifestations. The presence of these features should alert clinicians to the possibility of CNS involvement. The prognosis of such patients is poor despite aggressive systemic and local treatment and reflects the underlying disease biology. Application of allogeneic transplantation and administration of prophylactic CNS treatment are also discussed. Further elucidation of the factors predisposing patients with high-risk disease features to CNS myeloma involvement is needed.