A neural controller is developed and used to regulate the temperature in a semi-batch pilot-plant reactor. The experimental unit employs a monofluid heating-cooling system to raise the reactor to the operating temperature, and then remove the heat generated by an exothermic reaction. A methodology for installation of the neural controller is presented. Preliminary experiments form the neural-network learning database. These involve regulation of the reactor by either an advanced control algorithm or by operator (manual control). The results suggest that such neural controllers can provide excellent setpoint-tracking and disturbance rejection.