Objective: To investigate the prevalence of occupational diseases and treatment implementation in migrant workers in Hunan, China, and to provide a scientific basis for related departments to develop preventive and treatment measures and social security system for migrant workers. Methods: A retrospective investigation was performed in 2015 to collect the information of occupational diseases in migrant workers, and age, type of work, type of occupational disease, and implementation of employment injury insurance for occupation diseases were analyzed. Results: The migrant workers with occupational diseases accounted for 50.43% (11 280/22 368) of all patients with occupational diseases in Hunan, among whom 99.4% (11 212/11 280) were male workers. The mean age of migrant workers with occupational diseases was 55 years. The types of occupational diseases involved 6 categories such as occupational pneumoconiosis and occupational skin diseases, totaling 42 legal occupational diseases; 98.31% of all migrant workers (11 089/11 280) had occupational pneumoconiosis. The main types of work were underground coal miners (62.42%) , heading drivers (29.79%) , and haulage workers (2.20%) in coal mines and non-coal mines. A total of 27.25% migrant workers with occupational diseases (2 072/7 605) enjoyed employment injury insurance, and 20.84% (1 585/7 605) did not receive any medical or life compensations. Conclusion: The occupational diseases in migrant workers in Hunan are mainly pneumoconiosis, and a large proportion of those with occupational diseases do not enjoy implementation of treatment. Coal mines and non-coal mines are the high-risk areas for occupational diseases in migrant workers and should be the focus of prevention and control.