The development of mobile applications is paramount to support users living in developing countries to improve their lives. One of the major research challenges is to develop a user interface suitable for such users. In this chapter we present the design process we applied in order to develop a mobile application oriented to farmers living in Sri Lanka. The application prototype developed so far has been evaluated against usability requirements and a usability evaluation framework has been devised, which can be used to replicate the tests as the application iteratively reaches its final release. This work represents a pilot study within a wider international research project aiming to provide real-time information to support activities related to livelihood delivered using mobile phone applications targeted to meet the needs of people in developing countries.