Abstract Carbon disulfide-induced neurobehavioral effects are well known and do not need further evidence. Carbon disulfide vasculopathy and the syndromic complex resulting in depression, loss of memory and concentration, and behavior disturbances have been widely demonstrated. Less known is the evolution of the symptomatology when the environmental conditions are consistently improved, that is, the reversibility or the progression of the dysfunctions observed. This paper reports on a neurobehavioral follow-up in a viscose rayon factory carried out, in intervals, from 1974 to 1990. Several successive improvements were implemented in the plant through the years, until finally, the most radical changes were made at the end of the Seventies and these resulted in exposure levels far below the current Threshold Limit Values. A total of 493 subjects were examined and some of them were reexamined up to six times. The last examination was completed in September, 1990. In this paper, studies by our group over the 15 years of monitoring are discussed. The results show that the general mental state, as measured by neurobehavioral methods, reflects past and current exposure. This point was explored by dividing the subjects into six groups on the basis of their length of exposure and year of examination and by comparing their performances. The results show that even exposure to levels of carbon disulfide not exceeding 8 mg/m 3 may induce absentmindedness and difficulties in perceptive abilities.