The article aims to reveal the nature and specifics of the alternative method of modern banking ‘Hawala’, which makes it on the one hand, extremely convenient for use by organized criminal groups, and on the other, difficult to be investigated and proven. The authors trace Hawala’s historical roots, referring to the ancient customary law, and point out the strict rules on which it operates. It highlights that, with the development of information technologies, the Hawala systems’ principles have found a new application, from which organized criminal groups benefit. The article clarifies how the Bulgarian legislation incriminates money laundering and the possible use of the ‘Hawala’ system for this and other criminal activities. Attention is paid to the Bulgarian experience in the investigation of a network of persons involved in the use of the Hawala method for concealing, particularly serious crimes. The conclusion is made that the Hawala phenomenon poses a serious threat to the rule of law in any country, and the Bulgarian legislation needs to be adapted in order to provide effective mechanisms to counter such non-conventional type of crime.