The article discusses the issues of international responsibility of States for the use of force and the effects of its use in the light of decisions of selected international and municipal courts. The standards of attribution are determined by the substantive rules of international law (primary rules) or by the general rules pertaining to the international responsibility of States, as formulated by the International Law Commission (secondary rules). The International Court of Justice's position on the responsibility for the use of force by State's organs or non-state actors rests on two main principles. The Court, first, adopts a restrictive definition of an armed attack, limiting the scope of the reliance on self-defence, and, second, establishes with regard to the actor (as opposed to the territory or the victim) strict and demanding criteria of complete dependence or effective control regarding the position of non-state actors in relation to the State's authority, thus limiting the possibility to attribute to the State the responsibility for the acts done by those non-state actors. As concerns the violations of the rules of the human rights law by non-state actors, supported by State's authorities, the European Court of Human Rights applies the standard of overall control with regard to the (non-state) actor. A similar standard is applied by both the International Criminal Tribunal for the former Yugoslavia and the International Criminal Tribunal for Rwanda. The standard seems reasonable and solid. Essentially, it allows for a much easier attribution of international responsibility to a given State for acts of non-state actors. In the case of violations of the rules of the human rights law by extraterritorial acts of State's organs the European Court of Human Rights applies a standard of effective control – either regarding the territory or the victim of such violations. The thorny issue here is whether the term »within the jurisdiction« means »subject to the authority« of the State in question or »within the territory over which the authority is exercised« by that State. The criterion of effective control of a given territory does not always seem accurate as the criterion is not flexible enough to reflect the variety of situations that occur in practice. The international responsibility of a State depends on how one defines the actual control. The control may relate to the actor, territory or victim, to all acts or just some of them, may relate to a violation of the prohibition of the use of armed force or to a violation of international human rights/human rights law, may have a long lasting or short term character. Lastly, two addition factors should be taken into account – first, were those the acts of a State's organ or the acts of non-state actors; and second, were they done during the situation of an international armed conflict or the situation of an internal conflict.