ANUSAT, a micro-satellite developed by Anna University under the overall guidance of ISRO is intended to provide digital communication facilities between a number of universities / colleges and amature satellite radio operators. The thermal design of the satellite poses several challenges mainly because of its lower thermal inertia and power generation. This paper briefs about the thermal design for the ANUSAT, which uses passive thermal control system. No thermal heaters are provided because of the limited power generation. With this thermal design, predicted temperatures are expected to be well within the thermal operating limits. The in-orbit data for the ANUSAT confirms the judicious selection and effectiveness of the thermal control system.