Magnesium based hybrid composites with carbon fiber, SiCp and in-situ Mg2Si reinforcements have been prepared by squeeze infiltration technique. The results of the studies done on the measurement of the coefficient of thermal expansion after thermal cycling shows initially a rapid increase in the thermal expansion behaviour which gets stabilized after few thermal cycles. The thermal cycling after thermal treatment of the hybrid composites shows an increase in the coefficient of thermal expansion of these hybrid composites.