In this study, ultra fine-grained microstructure was produced in Al-Zn-Mg-Cu alloy by equal channel angular pressing (ECAP) at 200 degrees C and a pressing speed of 2 mm s(-1) using route C. The microstructure of the specimens was characterized by transmission and scanning electron microscopes. The results showed that the mean grain size of the specimens effectively decreased with increasing pass number. That is, while the grain size of unECAPed specimen was 10 mu m, this value decreased to 300 nm after 14 passes. High temperature tensile tests were carried out at a strain rate of 1 x 10(-2) and temperature of 250 degrees C in the specimens with different pass number. It was seen that the flow stress decreased and the elongation to failure significantly increased with increasing pass number. The highest elongation to failure value of 90% was obtained in the specimen after 14 passes.