Every nation when conferring citizenship seeks to select the most loyal, law-abiding and adjusted to life in the new state migrants. Due to this, involving the interested persons in the new community and serves as a number of requirements the performance of which show this, lawmakers set the interested persons are involved in the new community and serves as a basis for providing the citizenship of the country of residence. The article examines the procedure for naturalization by residence with requirements to acquire Spanish nationality and the requirements for the applicants for Spanish citizenship. The author highlights the requirements to be performed to obtain the notice on the decision of state authorities and after obtaining the affirmative decision. Prior to the 2015 reform, it was required to submit the documents in printed form, the compliance of the candidates for naturalization under law, the integration law was applied upon the interview with judge in charge of the Civil Registry, who decided whether the applicant meets the naturalization requirements or not. Currently, to confirm integration into the host society, candidates for naturalization in Spain are to pass two exams to obtain the Diploma of Spanish as a Foreign Language (DELE) and the Certificate of knowledge of the Spanish constitution and the Spanish social and cultural reality (CCSE). Recently, the EU countries draw more attention to the state language proficiency and the competence on the knowledge about the receiving state and community. Spain introduced the formal requirements later than other EU states. The author concludes that with the introduction of appropriate examinations, the evaluation of the social and cultural integration of applicants for naturalization has become more objective.