With the ever growing complexity of computer-controlled systems, the need for discrete- event systems has emerged. Many contributions have been done to improve and dis- cuss discrete-event system properties. In this thesis, we investigate the problem of fault tolerance in timed discrete-event systems. Our goal is to establish a timed fault tolerant supervisory control approach. We start by presenting our settings and providing different fault scenarios. We then provide four fault tolerant definitions to verify that the system will remain controllable in each scenario. Also, we introduce algorithms to verify timed controllability for each scenario. We implement a tool extension for the software research tool, DESpot, to verify timed controllability. Furthermore, we implement a tool extension to verify fault tolerant untimed controllability and nonblocking, and timed fault tolerant controllability for the fault scenarios. Finally, we present a simple example to illustrate our approach. / Thesis / Master of Applied Science (MASc)