A series of high-temperature-resistant polyimide/montmorillonite (PI/MMT) nanocomposite foams were prepared by solid blending method. The dispersion of MMT and effects of MMT content on the properties of the PI/MMT nanocomposite foams were investigated. Results indicated that MMT could be exfoliated effectively and dispersed uniformly in the PI matrix by the solid blending method. The introduction of MMT could considerably increase the reduced compressive strength, thermal resistance, and decrease the dielectric constant of the PI/MMT nanocomposite foams. The reduced compressive strength of nanocomposite foams showed a maximum value at the MMT content of 5 wt%, which was 197% higher than that of pure PI foams. It was worth noting that a significant increase in glass-transition temperature (T-g) could be achieved with the increase of MMT content, and the maximum T-g was as high as 436 degrees C at the MMT content of 7 wt%. This study may provide a useful method to prepare PI/MMT nanocomposite foams with improved properties for targeted high-temperature applications. POLYM. ENG. SCI., 51:1397-1403,2011. (C) 2011 Society of Plastics Engineers