PEEK is characterised by high impact and fatigue resistance andTg of 145‡C. Blends of PEEK and PEI have been made and scanning electron micro-graphs of the broken specimen show that the two polymers are completely miscible in all proportions. The study also shows that PEEK∶PEI 50∶50 blend, can be used as matrix for composite applications with appreciable enhancement ofTg to 177‡C.