In this paper we present the evaluation of contact materials for a MEMS thermal switch. The contact materials considered were liquid-metal micro-droplets and aligned carbon nanotube arrays. Five switch configurations were tested. The thermal interfacial resistance of the switches was measured. The liquid metal switch had a minimum thermal interfacial resistance of 1.1 mm2 K W-1. The minimum thermal interfacial resistance of the best carbon nanotube thermal switch was 20.4 mm2 K W -1. The ratio of the switch off to on thermal resistance was measured for each configuration. Based on these measurements, a switch incorporating liquid-metal droplets is found to be superior to switches incorporating aligned carbon nanotubes.