This work is concerned with the design of a single-user-mode computer-based examination system. It focused on trends in online computer based examination and carried out a critical review of current paper-based test system employed in Senior Secondary Schools in Nigeria. An alternative system to provide solutions to the current challenges identified in the existing system was then proposed. The system was designed using the object SSADM methodology and implemented using rapid PHP IDE on a Windows 10 system, using PHP, HTML, CSS and MySQL technologies and Apache server as the application server. Source Code folder for the designed CBT system is available at https://villagemath.net/journals/ver/v3i1/ABAH-HONMANE-AGE-OGBULE-CBT.zip with the Installation Guide and Setup information provided in Appendix A.