Cryoglobulinemia represents an emerging cause of peripheral neuropathy, especially in Southern Europe, in view of its relationship with hepatitis C virus infection. In a series of 100 consecutive referral patients with uncharacterized peripheral neuropathies, we systematically investigated cryoglobulinemia to assess its diagnostic yield. The most frequent diagnosis was hereditary neuropathy (33%), 29% were acquired neuropathies of different types, and no cause could be identified in 27%. Cryoglobulinemic neuropathy was diagnosed in 11 patients (7 women and 4 men), aged 54-77 (mean = 63.5 years), most presenting with sensory polyneuropathy, often asymmetrical. Cryoglobulin was also detected in 2 additional patients in whom a final diagnosis of non-Hodgkin lymphoma was made. Purpura was absent in 4 patients (and in 2 with lymphoma), or restricted to discrete manifestations in the remaining patients, which did not provide a clue to the diagnosis. Thus, search for cryoglobulin proves useful in a substantial number of undiagnosed peripheral neuropathies (11% to 13% in our series), even in the absence of typical skin lesions, and it is recommended as a first-line investigation in patients with unexplained neuropathy presenting in middle to older age.