The basis of the European Convention on Social Security consists of the four basic principles of international social security law, to wit: equality of treatment, single set of legislation applicable, maintenance of acquired rights and rights in the course of acquisition, and the payment of benefits abroad.
The following parts of the Convention are immediately applicable :
the general provisions, covering, in particular, the definition of the substantive and personal field of application of the Convention and the fundamental principles of equality of treatment and maintenance of acquired rights;
the provisions which determine the legislation applicable;
the parts concerning the cumulation of periods conferring entitlement and the calculation of benefits in all branches covered by the Convention;
the special provisions governing invalidity, old age and survivors pensions, and compensation for occupational accidents and diseases; and
the miscellaneous, transitional and final provisions.
The application of special provisions concerning sickness and maternity, unemployment and family benefits, with the exception of the cumulation of periods, however, remains subject to the conclusion of bilateral or multilateral agreements between the Parties.
The Convention is applicable to all legislation relating to the branches of social security concerning:
a. sickness and maternity benefits;
b. invalidity benefits;
c. old-age benefits;
d. survivors benefits;
e. occupational injury and disease benefits;
f. death grants;
g. unemployment benefits;
h. family benefits.
The Convention applies to all persons who are nationals of a Party - as well as refugees or stateless persons resident in the territory of a Party - and who are or have been subject to the legislation of one or more of the Parties, as well as the members of their families and their survivors. The provisions of the Convention shall also be applicable to the survivors of persons who, without having been nationals of a Party, were subject to the legislation of one or more of the Parties, where the survivors are nationals of a Party.
The Supplementary Agreement (CETS No. 078A), opened for signature by the member States of the Council of Europe which have signed the Convention, in Paris, on 14 December 1972, and entered into force on 1 March 1977, contains the provisions necessary for the application of the Convention norms which are immediately applicable. It covers, among other things, relations among social security institutions and procedure to be followed for settling and paying benefits that are due in conformity with the Convention. It also acts as a guide for the Convention provisions which will not be applicable until bilateral agreements have been concluded.