Introduction. Despite the technological modernization of the nickel industry, workers employed in it continue to be at increased risk of developing occupational pathology. The study aims to assess occupational health risks in the electrolysis production of nickel according to the longitudinal epidemiological study. Materials and methods. Experts have studied the data of workplace certification, periodic medical examination (2008) and the register of occupational diseases of the Murmansk region in 2009-2021. Results. In 2008, scientists identified 3,744 chronic unprofessional diseases in 1,397 nickel electrolysis workers, among which the most common were diseases of the musculoskeletal system (23.0%). 41.9% of workers had a low, 17.7% - moderate, 16.7% - medium, 10.7% - high and 12.9% - very high category of risk for the development of professional pathology. During the next 13 years (2009-2021), the authors have diagnosed 201 chronic occupational diseases for the first time in 89 employees, mainly respiratory organs (58.7%) and musculoskeletal system (28.9%). In total, occupational diseases were formed in 6.4% of workers, including 13.6% of cleaners, 7.6% of repairmen, 6.6% of electrolyzers, 5.7% of crane drivers, 4.9% of hydrometallurgical apparatchiks and electricians. Occupational morbidity was 114.31 per 10,000 workers with the highest rates in cleaners (328.69). We have detected occupational diseases in 1.0% of workers with a low risk category, 2.8% with moderate, 6.8% with medium, 13.3% with high and 22.2% with very high. Limitations. The impossibility of completely eliminating the possibility of diagnosing an occupational disease in workers who have dropped out of the observation group to other regions of the country. Conclusion. Researchers have obtained new data on the formation of occupational pathology in the electrolysis production of nickel, taking into account the specialty of employees and the category of occupational risk. Ethics. We carry out the study in accordance with the principles of the Helsinki Declaration. The protocol and design of the study were approved by the local committee of the North-Western Scientific Center for Hygiene and Public Health of 12.05.2021, Protocol No. 35.4.