The aim of the study was to assess the functional state of the autonomic nervous and cardiovascular systems of workers employed at the thermoshaft oil production. material and methods. Our test group No. 1 was consisted of operators dealing with blowing of wells. Their average age accounted of 30.5 ± 5.1 years; average underground experience amounted to 6.5 ± 2.7 years. Our test group No. 2 included 20 workers who performed their working tasks only on the surface but who had had the underground experience in the past. Their average age was 39.8±6.4 years (p>0.05); average surface experience amounted to 6.4±3.1 years (p>0.05), underground experience - 7.9±2.3 years (p>0.05). Our reference group consisted of 23 office workers never exposed to any adverse occupational factors. Their average age was 31.3±4.6 (p>0.05); average working experience amounted to 6.5±3.4 years (p>0.05). Our research analyzed non-occupational and occupational risk factors, neurophysiologic testing, the examination of vegetative functions, and statistic data processing. Results. 88% of workers in the test group No. 1 had “vegetative” complaints, whereas only 13% had apparent symptoms related to such disorders. Clinical examinations revealed vegetative dysfunction signs in 100% workers in the test group No. 1; in 62% workers in the test group No. 2 (t>2, p<0.05,χ2=10.1); and only in 29% workers in the reference group (t>2, p<0.05, χ2=23.9). Neurophysiologic testing allowed revealing workers from the test group No.1 to show attention decrement and an increase in the speed of mental responses by the end of their work shift. 24% had increased blood pressure, both systolic (up to 152.3±8.4 mm Hg) and diastolic one (up to 87.4±13.7 mm Hg). The absolute risk for workers from the test group No. 1 amounted to 0.8 as per detected functional disorders. It amounted to only 0.2 for workers never exposed to adverse occupational factors. Conclusion. Occupational activities performed by workers employed at thermoshaft oil production result in chronic fatigue. Neuropsychological and physical overloads lead to a decline in adaptation reserves of a body, vegetative disorders, and vascular tone dysfunction, which may be the arterial hypertension predictor.