SUMMARY
Concept and features of legal custom is an important and complex problem of contemporary juridical science. At the same time, unambiguous unified definition of legal custom can hardly be achieved due to the pluralism of legal thinking. For formulation the author's definition of the legal custom, it is necessary to distinguish its features by dividing them into the main and additional (optional), and based on the main features to construct the definition of this concept.The main features of the legal custom are common to all, without exception, these customs and additional (optional) – those that are present in many legal customs, but not all. The main ones are the following: established in practice, normativity, generality, compliance with law, recognition by society and actual legal validity. Thus, legal custom is established in practice and compliant with law general rule of a conduct (or its complex), which has actual legal validity and recognition by society. Additional signs of the legal custom complement and extend the palette of this concept, but are not binding for its existence.Optional (additional) features of a legal custom can be provided a little more than the main ones. This may be explained by the number and diversity of legal customs. In particular, they are: justice, rationality, ancientness, continuity, static, ethnicity, compulsory, sanction, incorporation into the system of law, provision of state coercion, unwritten form, certainty, variability, utility, consistency, anonymity and collectivity of authorship