Criminal procedure refers to the adjudication process of the criminal law. While criminal procedure differs dramatically by jurisdiction, the process generally begins with a formal criminal charge and results in the conviction or acquittal of the defendant.

Currently, in many countries with a democratic system and the rule of law, criminal procedure puts the burden of proof on the prosecution – that is, it is up to the prosecution to prove that the defendant is guilty beyond any reasonable doubt, as opposed to having the defense prove that s/he is innocent, and any doubt is resolved in favor of the defendant. This provision, known as the presumption of innocence, is required, for example, in the 46 countries that are members of the Council of Europe, under Article 6 of the European Convention on Human Rights, and it is included in other human rights documents. However, in practice it operates somewhat differently in different countries.

Similarly, all such jurisdictions allow the defendant the right to legal counsel and provide any defendant who cannot afford their own lawyer with a lawyer paid for at the public expense (which is in some countries called a "court-appointed lawyer").