We analyzed the clinical characteristics of 18 patients (13 female, 5 male) who had autoimmune autonomic neuropathy (AAN) and ganglionic acetylcholine receptor (AChR) autoantibodies. Mean age was 61.4 years (standard deviation, 12.0 years). Ten patients had subacute symptom onset, six with an antecedent event. Eight patients had chronic AAN, characterized by insidious symptom onset, without antecedent event, and gradual progression. A majority of patients with high antibody values (>1.00 nmol/L) had a combination of sicca complex (marked dry eyes and dry mouth), abnormal pupillary light response, upper gastrointestinal symptoms, and neurogenic bladder. Chronic AAN segregated into two subgroups. One subgroup (N = 4) had low antibody titer (0.09 +/- 0.01 nmol/L) and a paucity of cholinergic symptoms. It was indistinguishable from pure autonomic failure. The other subgroup (N = 4) had high antibody titer (11.6 +/- 2.08 nmol/L), sicca complex, abnormal pupils, and neurogenic bladder; three had severe upper gastrointestinal dysfunction. Higher antibody titers correlated with greater autonomic dysfunction and more frequent cholinergic dysautonomia. These observations expand the clinical spectrum of AAN to include chronic cases, some being indistinguishable from pure autonomic failure, and support the concept that ganglionic AChR antibodies are important diagnostically and pathophysiologically in acquired dysautonomia.