The analysis referred to 64 Polish cases of computer fraud (Art. 287 of the Penal Code (PC)) in which the preliminary proceedings were terminated in 2002 and first half of 2003. Relatively great number of cases consisted in issuing false invoices and falsifying accounting documents as well as falsifying bank accounts records and other bank documents. Attacks on records on the computer information carrier mainly served to appropriate and embezzle money. In these cases the behaviour of perpetrator fulfilled the features of the offence of misappropriation (Art. 284 § l of the PC) or common fraud (Art. 286 § l of the PC), and changes of data made on computer information carrier constituted a means to reach the purpose, i.e. appropriation of money.