The interests of justice are embedded in Article 53 (1) of the Rome Statute of the International Criminal Court (Rome Statute). They give the Prosecutor the right to decline to initiate an investigation or suspend a prosecution. In these cases, the interests of justice act as a basis for the Prosecutor to refrain from any action. This article argues that due to their non-positivist character, the interests of justice could serve as the platform also of prosecutorial action, acting as the legal vehicle for a broad interpretation of the Rome Statute in the name of justice. Nevertheless, such broad, interests of justice-instigated interpretation, cannot but have positivism as its outmost limit. The Rome Statute is an international criminal law instrument and international criminal law is governed by the legality principle, which narrows any hermeneutical endeavors. Along these lines, this article examines the nexus between the expansive interpretational interests of justice function and its limits by referring to cases where the International Criminal Court (icc) was called to endorse or not a broad interpretation of notions included in the Rome Statute. The article examines cases arising from situations referred to the icc by States and by the un Security Council.