Both ethics and advertising are two key elements of a business, whether small or large. Without ethics in a company, there would be no honesty, fairness and positive image of it; without advertising, the market duration of a company would be impossible. I decided to address this particular topic mainly due to the special significance of ethics in today's business world. The paper consists of a theoretical and a practical part. The former provides information about ethics and marketing, with a focus on the reasons why the use of aggressive advertising can be considered unethical. The latter presents the findings I arrived at by analysing instances of aggressive advertising encountered in the online environment. The case study was based on a questionnaire and a content analysis as research methods, in an attempt to find out how aggressive advertising is perceived and why it may be considered unethical.