Equal-channel angular pressing (ECAP) was conducted using dies having two different channel angles, Phi = 90degrees and 135degrees, for grain refinement of a Cu-38%Zn-3%Sn alloy. Orientation image microscopy (OIM) was used for microstructural observations and phase identification including the analysis of misorientation angles. Tensile testing and upset testing were carried out at elevated temperatures to examine the superplastic ductility and the formability of the alloy. The grain refinement was achieved effectively by conducting the ECAP at a temperature where a phase transformation occurs. The use of a die having Phi = 90degrees led to a finer grain size with a larger fraction of high angle grain boundaries than using a die having Phi = 135degrees.