Two patients with paraprotein-associated peripheral polyneuropathy were treated successfully using immunoadsorption of patient's plasma with staphylococcal protein A. Both had previously been treated with immunosuppressive agents or plasma exchange, and were rapidly relapsing at the time of their protein A immunoadsorption therapy. One patient was treated "on-line" with a blood cell separator, and one was treated "off-line." Both responded well to therapy with minimal toxicity. Serum levels of circulating immune complexes were elevated in one patient and remained so during and after therapy. Immunoadsorption with protein A should be investigated as a therapeutic option for patients with paraprotein-associated peripheral polyneuropathy. The therapy is relatively easy to administer, particularly "off-line," and was well tolerated by our patients. More experience, including formal clinical trials, will be required to properly define the indications for, and mechanism of response to, this therapy.