Within that which can be characterized as an expansive tendency of the Social Security System, the common services of Social Security for the management of technical payments of various types -work security, hygiene, formative action, reeducation and rehabilitation of the handicapped and pensioner assistance- appeared at the beginning of the 1970s.

The NATIONAL INSTITUTE OF SOCIAL SERVICES (INSERSO), approved by Royal Decree-Law 36/1978, of November 6, began operating the Social Sercurity System's complementary services and continued to do so until the Royal Decree 530/1985 of April 8, in its third additional article, introduced a fundamental change: it gave INSERSO some of the functions of the defunct National Institute of Social Assistance (INAS) which menat that its management activities overlapped the limits of the Social Security System. This integration or universalist direction of INSERSO was complemented by other subsequent articles: in particular, the Royal Decree 1433/1985 by which the management of the Institute was expanded and for the first time included new groups and new regulatory mechanisms: senior citizens, the physically and mentally handicapped, refugees and the marginal population. In this way, concurrence of ways and means, representing a launching pad for the universal regulation of social services came about.

The obligations and responsibilities of INSERSO regarding the management of the complementary services of Social Security benefits were transferred, as of Jaunary 1, 1991, to the Governments of the Autonomous Communities of Catalunya, Andalucia, Galicia, Valencia, Canary Islands, Basque Country and Navarre.