The association of chronic inflammatory demyelinating polyneuropathy (CIDP) and carcinoma has rarely been reported and its relevance is debated. Thirty three consecutive patients with probable or definite CIDP (idiopathic or associated with M protein) were investigated. Three patients with definite CIDP had a concomitant carcinoma. One had an IgM paraprotein. Steroids and intravenous immunoglobulins were effective.