The purpose of this bachelor’s thesis is to study the importance and effects of user experience oriented design to the conversion rates and profitability of web stores and eCommerce. This thesis was conducted in a form of a literature review. The main tools used for accessing reliable existing studies and researching source materials were electronic databases and electronic libraries, such as IEEE Xplore Digital Library, provided by Institute of Electrical and Electronics Engineers, AISeL, electronic library of Association for Information Systems and Google Scholar. Some source material was found in traditional books related to the field of information systems science. The search for source material was done using keywords, such as User Interface, Usability, User oriented design, ease of use, User Experience, eCommerce, eBusiness, Conversion Rate and their Finnish equivalents. Most of these concepts are defined in the second chapter of the thesis, followed by an introduction of different design models and principles in the third chapter. The fourth chapter contains the results of the research, which implicate correlation between good user experience design and the success of web stores, which confirms the hypothesis of this thesis.