The Welfare Subsystem, which is a contributory scheme, covers most employees or similar workers and also the self-employed (although the latter are subject to special conditions). Its aim is to provide financial support to workers who lose their employment income in the following circumstances: sickness; maternity, paternity and adoption; unemployment; occupational diseases; invalidity; old age; and death (survivorship and supplementary support for dependants). In the case of the self-employed, the compulsory protection scheme gives entitlement only to financial support in the following circumstances: maternity, paternity, adoption, unemployment, occupational diseases, invalidity, old age, and death (survivorship and supplementary support for dependants). They may, however, choose a broader protection scheme, based on higher-rate deductions, in which case they also benefit from support in the event of illness.

Employees are entitled to receive benefits only if they are enrolled in the public social security system. Enrolment for social security is for life.

Employers are required to advise the social security system when they hire new workers and to enroll workers not yet registered with the social security system. Every time an employee signs a contract of employment, he also has to advise the social security system of the name of the new employer within 24 hours of the start of a contract, via the District Centre website Segurança Social Directa (Direct Social Security)), by filling in the appropriate form.

Both the employer and the employee enrolled in the social security system are required to pay contributions. The rates generally applicable are 23.75% for employers and 11% (deducted at source from gross pay) for employees.

The self-employed have to pay monthly contributions at a rate of 25.4% of their declared income (if covered by the compulsory protection scheme alone) or 32% (if they opt for the broad protection scheme) of the pay scale chosen by them.