Management of some diverse complications of plasma cell myeloma is reviewed with respect to prevention when possible and prompt treatment when necessary. A series of 102 patients from the Duke University Medical Center was surveyed to ascertain the approximate frequency with which renal failure, hypercalcemia, infection, hyperviscosity syndrome, and neurologic disorders occur. Selected patient studies and additional data from the literature emphasize aspects of these complications amenable to therapy aside from that directed at plasma cell growth.