The financial services sector is investing considerable sums of money into mobile banking services, but the uptake by customers has been low. The cost to benefit ratio of mobile banking is highly unsatisfactory when the costs of developing and managing the channel are considered. Many of the advantages of Internet banking are shared by mobile banking e.g. control and time saving. Mobile banking also offers higher convenience with the ability to carry out banking whenever and wherever you are. It is hoped that mobile banking can be as successful as Internet banking. A major factor in the low adoption of mobile banking is usability, and there is a need for research on the issues surrounding mobile banking as so far little has been conducted. This thesis seeks to investigate the usability issues surrounding Short Message Service (SMS) banking. It identifies three general functions of SMS in electronic banking: transactions, communication/CRM and security. Three empirical usability evaluations are presented that explored customers’ perceptions and attitudes of using these functions of SMS banking. The research presented here provides empirical evidence for the thesis that usability is a significant factor in the low customer adoption of SMS banking. It also shows that related to usability issues are customer concerns over the security of SMS as a banking channel. Older users will find SMS banking less usable than younger users and are more ambivalent regarding SMS in general. It recommends the most usable message input format to use in SMS banking and contributes insights on how best to realise the practical application of SMS banking and services. The findings from these studies will help improve usability in mobile banking services.