Effectiveness versus procedural protection : tensions triggered by the EU law mandate of ex officio review Die Arbeit untersucht das Spannungsfeld zwischen einem fairen Resultat und Fairplay im Rechtsverfahren. Bislang hat der Europäische Gerichtshof es traditionell abgelehnt hier eine klare Wahl zu treffen indem er sich in Vorabentscheidungen im Zusammenhang mit der ex officio Überprüfung weitgehend dem nationalen Recht unterwirft. Diese Arbeit zeigt dass spezifische Schutzvorrechte zunehmend substantiell korrekte Urteile hervorgebracht haben während ein neuer Grundrechtsansatz den individuellen Verfahrensschutz nicht gefördert hat. This study deals with the friction that arises when the effectiveness of EU law encounters national rules which prevent judges from applying EU law on their own initiative. It presents pivotal factors in the CJEU’s endeavours to strike a balance in a way that ensures both substantive and procedural protection. The author lends her support to a theoretical approach of distilling the beneficiaries of effectiveness effective judicial protection under EU law and national standards of procedural protection. This methodological lens locates a key dividing line between ensuring the substantive protection of a beneficiary of EU law and ensuring procedural protection for all litigants.Requiring a national judge to examine applicable EU law ex officio is the solution that best promotes its correct implementation i.e. substantive protection. Yet this is a controversial duty to stipulate because it runs contrary to the principle of party disposition. While by and large respecting procedural autonomy the conditioned obligation of ex officio review identified in this work has the capacity to undercut procedural equality.