This paper discusses computer crime and its impact on the security of the marketing - information system. The focus of this paper is on explanation of the impact that computer crime has on the company and ways to prevent and protect the marketing information system. Since there is no generally accepted definition of cybercrime, in order to better define it, special attention is paid to the type, means, methods and consequences of committing the crime of cybercrime. Cybercrime is closely linked to computer technology and the Internet, which includes marketing - information systems that aim to provide the information needed to make marketing decisions. As computer technology becomes more and more an indispensable and irreplaceable part of human life and work, the danger of computer crime also grows. That is the reason that more and more resources are being invested in the development of various methods and means of protection, which will ensure the smooth operation of the company. The first part of this paper studies marketing - information systems as a necessary part of every business. Since modern MIS is based on the use of computer technology and the Internet, the origin and detection of cybercrime, its types and methods and means of cybercrime prevention are studied in detail. Based on practical examples, this paper presents the consequences of computer crime and the possibilities of solving this problem. It is clear that the development of technology, in addition to a number of positive effects on the development of the market and business, also brings with it various risk factors. Therefore, the issue of data security and systems of data protection is becoming an increasingly important factor in the business of every company in modern business conditions.