Ninety asbestosis patients were examined clinically with special emphasis on the function of the peripheral and the central nervous system. Serum specimens were analyzed for carcinoembryonic antigen(s) (CEA), ferritin, and beta 2-microglobulin (beta 2m) content. The patients were classified into four subgroups: (1) those with peripheral neuropathy, (2) those with involvement of central nervous system, (3) those with both types of neurological signs, and (4) those with normal neurological status. The levels of serum CEA, ferritin, and beta 2m were elevated in all four subgroups. No statistically significant differences were found between the groups in the prevalence of elevated values of the three tumor markers (equal or above the following limits: CEA, 5 micrograms/liter; ferritin, 400 micrograms/liter, and beta 2m, 3 mg/liter). The patients currently smoking had a higher level of serum CEA than nonsmokers or exsmokers, but the differences were not statistically significant. In the subgroup that comprised those asbestosis patients in whom the disease could be considered progressive according to the ILO 1980 classification of the chest radiographs, the mean level of CEA in serum was higher than that of the patient group without such progression of the disease (p less than 0.05, Student's t test). Although the prevalence of abnormal neurological signs was high in these asbestosis patients, no obvious correlation was found between the neurological findings and the tumor markers studied.