The article is devoted to the study of the criminological features of professional crime, which is an important and relevant issue for shaping the system of measures aimed at its prevention and counteraction. Professional crime refers to the criminal activities of individuals who systematically, throughout their lives, commit criminal acts in a specific field, using the results of these activities as a means of earning or gaining profit for their livelihood. For such individuals, their specific “criminal activity” becomes a “profession” in which they develop, continually improve their criminal skills, and reach professional “heights” to maximize profits (income) and hide the traces of their criminal activities from law enforcement. The authors identifies the following characteristics of professional crime: its persistent and stable nature; the presence of “specialization” and “qualification” in the offender; the regular income (profit) from criminal activity; the offender’s constant connection with an antisocial environment; and the existence of a specific “subculture” in the form of traditions, customs, and particular “languages of communication” (slang). Based on the research, the authors has formulated a system of economic, social, political, and legal measures to prevent and counter professional crime. As part of the legal measures, the author proposes amending different articles of the Special Part of the Criminal Code of Ukraine by adding a new qualifying feature: “the commission of an act in the form of criminal activity.” Currently, the only qualifying feature in the Criminal Code of Ukraine is “repeat offense,” which applies whether two episodes of a crime have been committed or even if there have been 3-15 episodes of the same crime. This approach fails to account for the activities of professional criminals, where the commission of 3-15 crimes should be qualified as a more serious offense compared to ordinary “repeat offenses,” which only cover two episodes. The authors also suggests the creation of a separate law, the “Law of Ukraine on the Basics of Prevention and Counteraction to Professional Crime,” which would include specific sections ensuring comprehensive regulation of the issue of combating professional crime. The structure of these sections may include: 1) “General Provisions”; 2) “Subjects of Countering Professional Crime, Their Competence”; 3) “Preventive and Countermeasures Against Professional Crime”; 4) “The Identity of the Professional Criminal and Their Legal Status”; 5) “Liability for Violations in the Sphere of Countering Professional Crime”; 6) “Control and Supervision over the Enforcement of Laws in the Fight Against Professional Crime”; 7) “Final and Transitional Provisions”. In the author’s opinion, a comprehensive legislative regulation of professional crime and the formation of an effective system of measures to counter it are key to building a successful preventive criminological policy of the state in the fight against such crime.