Purpose: Interactivity and simplicity of navigation make users browse a website, and its usefulness is the main factor which influences the intention of using it to buy a product or service. The aim of the paper was to identify the most frequent project errors that negatively impact the usability of websites of agortourism farms. Design/methodology/approach: The surveys were carried out by the audit method in a set of websites which were grouped according to accepted categories. The audit was based on a heuristic analysis using a control list. Findings: A number of usability problems have been identified in the set of examined websites; however, the most important were the lack of explicit updates or the presentation of outdated information, as well as the dysfunction of forms – contact and inquiry. Zero-category sites are unusable. They are characterised, among others, by no visible updates (or presentation of outdated information), archaic technique of execution, often based on so-called “Frames” (iframes) or tables, as well as imperfect, archaic graphic design. Originality/value: The usefulness of a website (reflected in the design details) goes into the background when it only serves an information and contact function and does not provide advanced functionalities, such as, for example, an accommodation booking form. In the case of agrotourism farms, the most important elements are the thematic graphic design and exhaustive content.