In the article the author discusses whether polygamy and interfaith marriages are permissible according to Sharia, fiqh and recent legislation of some Muslim countries.

The article aims at identifying whether the mentioned questions are regulated equally in accordance with Sharia, fiqh and current family laws. In case the regulation is various, it is necessary to give the answer what is the reason for such a discordance, as the basis of the state is the same - Sharia.

The methodology of this work is based on the differentiation of the terms ‘Sharia’, ‘fiqh’ and ‘Islamic law’, as synonymising them, a person might come to incorrect conclusions.

The author gives some basic postulates of an Islamic marriage and analyses it not only from a theoretic perspective (Sharia and fiqh), but also from a modern legislation one, which provides some practical significance to the research and gives an opportunity to apply the conclusions.

As a result of this research the author concludes that interfaith marriages and polygamy are permitted in the context of Sharia and fiqh; while in the legislation of the countries accepted to be Islamic, the question on polygamy is sometimes solved completely differently from Sharia ideas.

The mentioned discordances, various interpretations of Sharia and fiqh are, on the author’s opinion, connected with the process of globalisation. Although it has plenty of advantages, still there is one crucial drawback - ‘equalisation of countries’, which results in the loss of the identity of the countries engaged in the globalisation. This gives some ground to think over unification of family law in Arabic countries, as their norms regulating family relations deprive from one source.