The main subject of this study is the vendor?s style in user interface design of contemporary mobile phones. It is investigated both from designers? points of view and users? points of view. Vendor?s style is concerned in the whole process of user interface design as consistency, building the vendor?s identity. UI designers have to understand the difference in the competitions? style in order to create a well-designed style with high usability. From the user?s point of view, the vendor?s style in user interface has a significant role in the initial usability when replacing a mobile phone. Two research questions that have arisen from these concerns about the vendor?s style and usability: 1.What is the vendor?s style of the user interface in a mobile phone?; 2.How does a vendor?s style in the user interface affect initial usability of mobile phones? In addition to usability, cultural influences in the vendor?s style are approached. Three authoritative manufacturers are selected based on different cultural backgrounds.The third research question about relationship between a vendor?s culture and style in UI is as follows:Is there a cultural influence in the vendor?s style?