Schengen ali območje brez notranjih meja in s skupno zunanjo mejo, je eden izmed največjih dosežkov Evropske unije, saj omogoča prosto gibanje oseb znotraj tega območja brez, da bi jih na mejah čakale kontrole. Usklajene kontrole se pa izvajajo na zunanji schengenski meji in s tem zagotavlja varnost in preprečuje kriminal. Ker so v letih 2015 in 2016 v Evropo po nezakonitih poteh skušali priti številni migranti je prišlo do migrantske krize, kjer je za azil v EU zaprosilo več kot dva milijona ljudi. To je za Evropsko unijo predstavljalo velik izziv, ki ga še danes ni uspešno rešila. Z migrantsko krizo so se pokazale pomanjkljivosti evropskega azilnega sistema, zaradi česar so nekatere države članice schengenskega območja pričele ponovno uvajati nadzore na svojih notranjih mejah z namenom zaustavitve prihoda prosilcev za azil in drugih migrantov na njihovo ozemlje. Zaradi tega je morala Evropska Komisija začeti oblikovati številne nove ukrepe za učinkovitejšo azilno politiko in s tem spremembo evropskega azilnega sistema, katerega cilj je, da se breme v zvezi z migrantsko krizo porazdeli med vse države članice. Cilj diplomske naloge je ugotoviti, ali smejo države članice ponovno uvesti kontrole na svojih notranjih mejah, ter pod katerimi pogoji in za kakšno časovno obdobje in kakšen vpliv je imela migrantska kriza na EU in scgengensko območje in s tem na ponovno uvedbo mejnih kontrol, ter ugotoviti, ali obstajajo še kakšni drugi, za prosto gibanje manj ovirajoči ukrepi, ki jih sme uporabiti država za preprečevanje nelegalnih migracij. V tem delu ugotavljam, da lahko države članice schengenskega območja izjemoma in v skrajnih primerih ponovno uvedejo nadzore na svojih notranjih mejah, na podlagi 25. člena Zakonika o schengenskih mejah, pri čemer mora biti uporaba tega ukrepa nujna, obseg in trajanje ukrepa pa mora biti natančno določen. Poleg tega Zakonik Unije o pravilih, ki urejajo gibanje oseb prek meja (Zakonik o schengenskih mejah) še določa uvedbo nadzora na notranjih mejah v v okviru predvidljivih dogodkov (kot so na primer športne prireditve), v primerih, ko je potrebno takojšnje ukrepanje za odzivanje na grožnjo in v primeru izjemnih okoliščinah, ko je ogroženo splošno delovanje schengenskega sistema zaradi trajnih in resnih pomanjkljivosti v zvezi z nadzorom na zunanjih mejah in če te okoliščine pomenijo resno grožnjo javnemu redu ali notranji varnosti države. Vendar pa ugotavljam, da nadzori na notranjih mejah na dolgi rok ne predstavljajo rešitve problema v zvezi z migrantsko krizo in množičnim prihodom migrantov na ozemlje Evrope, ampak zgolj ogromne, gospodarske, politične in socialne stroške za EU in za posamezne države članice, zato bi bila potrebna krepitev zunanje schengenske meje, pri čemer bi morale države članice na zunanjih mejah zavrniti vstop v EU državljanom tretjih držav, ki ne izpolnjujejo vstopih pogojev, ter državljanom tretjih držav, ki niso zaprosili za azil v državi članici, na katere ozemlje so prvo vstopili, kljub temu, da so imeli to priložnost. Schengen, also known as the area without inner borders and with joint external border, is one of European Union’s greatest achievements, because it enables people to move freely within this area without border control. However, coordinated control is exercised on the external border. This border control ensures safety and prevents crime. In the years 2015 and 2016 many migrants tried to smuggle into Europe illegally and more than two million of them asked for asylum in the EU. This occurrence lead to migrant crisis, which presented as a large challenge for the EU that has not been successfully solved to this day. Migrant crisis started to indicate imperfections of the European asylum system and for this reason some of the member states once again began to initiate control on their inner borders with purpose to stop the arrival of asylum applicants and other migrants on their territory. Because of that European Commission had to form numerous new measures for more efficient asylum policy and thereby change European asylum system. The aim of the system is to partition the burden of the migrant crisis among all member states. The objective of dissertation is to establish what kind of effect migrant crisis has had on the EU and Schengen area and with that on national security and safety of people. Furthermore I will establish if member states can initiate control on their inner borders, under what circumstances they can do that and for what time period. In addition I want to establis if there are any other measures thar are less hindering to free movement and can be used by countries that want to prevent illegal migrations. In this part I have established, that exceptionally and in extreme cases member states of the Schengen area can once again initiate control on their inner borders on the basis of article 25 of the Union Code on the rules governing the movement of persons across borders (Schengen Borders Code). Usage of this measure has to be pressing additionally, the scale and duration of this measure must be thoroughly explicit. In addition, Schengen Borders Code stipulates initiation of controls on inner borders in case of predictable events (for instance sports event), in urgent cases, when responding to grave threat and in cases under exceptional circumstances, when general activity of Schengen system is endangered because of permanent and grave imperfections concerning control on external border and when these circumstances signify a real threat to public order or inner security of the country. However, I have established that controls on inner borders do not pose a long-term solution regarding the migrant crisis and mass arrival of migrants on the European territory. They only create enormous economical, political and social expenses for the EU and individual member states. For this reason it would be necessary to build-up external Schengen border. Member states on the external borders should decline entry in EU to third-country nationals that do not meet the demands and third-country nationals that did not ask for asylum in the member state, on which territory they had first entered, although they had the chance.