Insured persons may participate in the program compulsorily or voluntarily. The following workers above 15 full years and below 65 years of age shall be insured under this program compulsorily:
- Industrial workers employed by public or private factory, mine, salt field, range, pasturage, forest or tea plantation with more than five employees, as well as workers employed by a communication or transportation enterprise, or by a public utility.
- Workers employed by a company or firm with more than five employees.
- Employees in a journalistic, cultural, non-profit organization or cooperative enterprise with more than five persons.
- Employees of government offices or public or private schools who are not legally entitled to join civil servants' insurance or the insurance of teachers and employees of private schools.
- Workers employed in fishing production.
- Persons receiving vocational training in vocational training institutes registered with the government.
- Members of an occupational union who have no definite employer or who are self-employed.
- Fishermen who belong to Class A of Fishermen's Association and are either self-employed or do not have a definite employer.
Besides workers who are insured compulsorily, employers concurrently engaged in laboring services and persons employed in enterprises with less than five employees may also participate in the program on a voluntary basis.
Insured persons in this program shall be covered via the employers, or the organizations or institutes to which they belong as the insured units.