In the modern period of the development of Big Data technologies and the growth of their economic importance, a new approach to determining the legal regime of personal data is required. The current situation, together with the maximum benefit from the economic potential of Big Data, requires optimal, balanced solutions to ensure the safety of people's personal lives. The article substantiates the need to improve the legal norms related to the collection and processing of personal data in the era of Big Data. Attention is paid to the relevance of the problem of recognition of ownership of personal data. The contradictions between the applied concepts of Big Data technologies with legal concepts related to the depersonalization of data on the private life of people, legitimation and restriction of their processing are analyzed (pp.28-33).