While assessing the proportionality of measures in the field of personal data gathered by intelligence services surveillance, the Court of Justice of the European Union (CJEU) and the Constitutional Court of the Republic of Lithuania attach the same significance to this principle as one of elements of rule of law in the interpretation of the Charter of Fundamental Rights of the European Union and other relevant pieces of the European Union legislation and the Constitution, respectively. Both courts use the general notion of proportionality that national measures undertaken must be proportionate to their objectives. However, the practice of both courts affirms that application of this principle in their practice is to some extent specific. According to the analysed case-law, not all structural components of the typical proportionality test are used by the courts. Based on comparative analysis, the chapter overviews this and the other most important developments in the recent case law of the CJEU and the Lithuanian Constitutional Court in the field of surveillance by intelligence services, and reveals specifics of the application of the principle of proportionality in cases of other clashes between individual rights and public interests: right to family life and public security, right to property and prevention of crimes, as well right to acquire and possess weapons and public security or public order. The chapter also suggests a possible direction for the future interrelation of jurisprudences.