The article discusses the discussion of concepts, nature and sources of financial law. Financial law is defined as an institution of private law held by the division of financial right to private financial law and public financial law Summing up, once again note that the traditional notion shall be of financial law as soon as institution (industry, sub-industry, etc.) of public law, do not disclose the true content of this important concept. In a market economy, financial law should be interpreted as an institution of private law, the content of which is made up of general and special rules of civil (entrepreneurial) law governing financial relations based on equality, autonomy of the will and the property autonomy of their participants. This approach does not detract from the importance of public law in regulating financial relations, but demonstrates their true place and importance in the mechanism for regulating financial relations.