Mobile devices have proliferated into most working and private areas and broad user groups have access to mobile technology. This has considerable impact on demands for usable designs. As users differ widely regarding age, upbringing, experience and abilities, it is a basic question whether there are user interface designs feasible that meet the demands of user diversity and trans-generational designs. The aim of the present research was to uncover effects of user diversity on menu navigation. Users of a wide age range were examined when interacting with mobile phones. In a detailed way, individual navigation routes were analyzed and effectiveness and efficiency of menu navigation was determined. In addition, effects of individual variables were considered. The results show that the usage of small-screen devices imposes considerable difficulties for all users, but in particular for children and middle-aged adults, who were very sensitive for cognitive demands imposed by current mobile phone designs.