Mobile phones are fast becoming a dominant delivery channel for services in developing countries. With almost one billion non-literate people in the world, the majority of them in developing countries, the need to create products and services that cater to communities with low levels of literacy is becoming more pressing. At present, effective use of almost all digital systems requires relatively advanced levels of literacy. The design of Motorola F3, a mobile handset designed specifically for non-literate people in developing countries is used as an example to show how some of these challenges can be overcome. It is shown that navigation and basic understanding of a service can be eased through simplification of the user interface to reduce cognitive load, and by encouraging the use of spatial and visual memory. In conclusion, a set of principles for the design of systems for non-literate people is presented.