The final paper theoretically defines and compares the activities and services of advertising agencies and public relations agencies. A content analysis of the websites of selected Croatian advertising agencies and selected Croatian public relations agencies was conducted. After analysis and comparison, it was found that advertising agencies give more space and put emphasis on projects they have worked for specific clients and on the visual identity of the website. Public relations agencies place emphasis on defining the services they can offer to their clients, as well as on the visibility and availability of the information needed by each visitor to their website. There are websites that follow the world’s leading trends and those that do not pay much attention to their own digital communication with the public through these channels, which varies from agency to agency. A qualitative survey of the attitudes of agency experts on differences in the performance and approach of clients between advertising agencies and public relations agencies was conducted. The expert's recommendation would be to follow the world's leading trends and invest in the up-to-dateness, relevance and clarity of the websites themselves, both advertising agencies and public relations agencies, because they are a mirror of what a particular agency can offer its clients.