On 6 December 1922, the National Assembly of Hungary passed a bill on unfair competition. The law was promulgated in May next year as Act V of 1923, and entered into force on 15 May 1924. We can see already from its title that its scope was very similar to that of today’s competition law: to ensure that business be done in accordance with honest practices. If we take a look at the subsequent jurisdiction of the courts in unfair competition cases, we may add to this conclusion that the most characteristic unfair market behaviours were surprisingly similar to the “tricky” business practices today’s competition and consumer protection laws are fighting against. This study aims to present why and how the first Hungarian unfair competition law was adopted, and what examples of unfair business practices were considered as most typical or dangerous, also expanding the focus to some similarities and differences with the competition law and practice of our time.