Background: During the last years, examination of autonomic nervous function and of autonomic neuropathy has attracted attention not only in diabetes mellitus research but also in other areas of internal medicine. However, patients with various chronic diseases with autoimmune phenomenons have never been investigated in a comparative study with standardized examination techniques. Hence, the aim of the study was to examine the prevalence and the severity of autonomic neuropathy in patients with the following chronic diseases., Patients and Methods: We investigated 28 patients with Crohn's disease (CD: age: 32.4 +/- 2.0 y), 17 patients with ulcerative colitis (UC: 39.7 +/- 3.6 y), 39 patients with systemic lupus erythematosus (SLE: 34.9 +/- 2.0 y), 38 patients with progressive systemic sclerosis (pSS; 51.5 +/- 2.4 y) and 65 patients with insulin-dependent diabetes mellitus (IDDM: 35.5 +/- 1.6 y). Cardiovascular autonomic (cANP), pupillary autonomic (pANP), and sensorimotor (ssNP) neuropathy were assessed by standardized techniques., Results: Prevalence rates for cANP, pANP and ssNP were found to be 0%, 19%, and 7% in CD, 6%, 25%, and 18% in UC, 5%, 29%, and 10% in SLE, 11%, 16%, and 32% in pSS, and 26%, 66%, and 29% in IDDM, respectively., Conclusion: The study demonstrated patients with IDDM to have the highest prevalence rates of cANP and pANP. Patients with other chronic diseases, particularly SLE, pSS and UC, had high prevalence rates of pANP. This may be due to alterations of structures of the central nervous system in these patients. cANP was rare in patients with inflammatory bowel disease and ssNP was found very often in patients with pSS, probably due to local fibrotic lesions. The various disease groups differ in the pattern and severity of autonomic and sensorimotor neuropathy, which indicates that different structures and neuropathogenic mechanisms may be involved.