The present study reports the principles of a new system, "equal-channel angular sheet extrusion (ECASE)", which has been designed and manufactured for continuous processing of IF-steel sheets. IF-steel sheets with 1.2 mm thickness and 200 mm width were processed using this system following route-A up to eight passes at room temperature. Microstructural evolution and mechanical properties were investigated as a function of number of passes. The ECASE process increased considerably both sigma(y) and sigma(UTS) values of IF-steel sheets. The sigma(y) after one pass was nearly twice as high as that of the as-received one. After eight ECASE passes, the sigma(y) and sigma(UTS) reached to about 499 MPa and 525 MPa, respectively, which were 2.6 times and 1.9 times higher than those of the as-received ones. However, the processed sheets show limited tensile ductility, which needs to be enhanced with further appropriate processes to be utilized in practice. It can be concluded that the use of ECASE provides a simple and effective procedure for improving the strength of IF-steel sheets.