The 500-MW(electric) Prototype Fast Breeder Reactor (PFBR) is currently under construction at Kalpakkam, India. A core temperature monitoring system is provided to monitor adequacy of core cooling and protect the reactor against design-basis events. Triplicated real-time computer systems and hardwired systems are used for monitoring subassembly outlet sodium temperature and reactor inlet temperature. This paper describes the core temperature monitoring system provided in PFBR.