Thirty-three patients with inflammatory-angiopathic neuropathy diagnosed by sural nerve biopsy, were investigated to determine the underlying disease. Twenty-six patients had symmetrical sensorimotor polyneuropathy and seven had mononeuropathy multiplex. An aetiology for inflammatory-angiopathic neuropathy was found in only eight patients: typical collagen vascular disease in five and malignant tumour in three. Sixteen patients received prednisone and/or immunosuppressive drug therapy and 12 (75%) responded to treatment. This study demonstrates that typical collagen vascular diseases are not the most common cause of inflammatory-angiopathic neuropathy, that symmetrical polyneuropathy is seen in 75.8% of inflammatory-angiopathic neuropathy patients. Prednisone and/or immunosuppressive agents appear effective regardless of aetiology.