Objectives:
The Spanish constitutional public order, regulated in the Constitution and in the organic law of religious freedom, makes it impossible to contract a second marriage if the first is in force even for religious reasons. Thus, matrimonial monogamy is protected by civil law and canonical matrimonial law, admitted by the current matrimonial system. The protection is in the prohibitions to contract a new marriage while the first is not dissolved, and for the existence of the crime of bigamy. Nonetheless, the Spanish Supreme Court has admitted the derived legal consequences of a polygamous marriage.

Material and methods:
Spanish matrimonial legislation: Civil code and agreements with religious confessions. the canonical and Islamic matrimonial rights, and the decision of the Spanish Supreme Court that admits civil effects of a polygamous marriage. The study was carried out in the Proyecto I + D + I DER2015-65840-R 'Diversidad y Convivencia: los derechos humanos como guía de acción', of the Programa Estatal de Investigación, Desarrollo and Innovación orientada a los retos de la sociedad, of the Ministerio de Economía y Competitividad.

Results:
Monogamy is protected by Spanish civil and penal law, indeed by canonical matrimonial law. The Supreme Court has admitted the legal consequences of a polygamous marriage.

Conclusions:
480/5000 In multicultural Spanish society different ways of understanding marriage can coexist, as long as they are compatible with the Spanish public order, where human rights are guaranteed. Polygamy is in evident contrast to the women's inequality. For this reason, polygamy can not be admitted in Spain, although concrete jurisprudential decisions to prevent unjust situations where the public order is weakened or atenuated.