We analyzed the mammographic (n=21) findings (location, margin, shape, cluster microcalcifications, size, multiplicity) and ultrasonographic (n=12) findings (shape, border, internal echo, boundary echo, posterior echo, lateral echo, width/depth ratio) to evaluate specific radiologic findings of histopathologically proved uncommon breast cancer. The mammographic findings (n=21) are as follow; 1) single; 16, multiple; 5 2) margin (smooth; 13, irregular; 4, spiculated; 4) 3) shape (round and ovoid; 9, lobulated; 8, irregular; 4) 4) cluster microcalcifications (abscent; 20, present; 1) 5) size (1-3cm; 18, 3-5cm; 2, 5cm> ; 1) 6) location (UOQ; 13, UIQ; 4, LIQ; 3, LOQ; 1). The ultrasonographic findings (n=12) are as follow; 1) shape (round to oval; 5, lobulated; 5, irregular; 2) 2) border (smooth even; 9, rough uneven; 3) 3) internal echo (fine homogeneous; 5, coarse heterogeneous; 7) 4) boundary echo (regular fine; 4, irregular thick; 8) 5) posterior echo (enhanced; 11, no change; 1) 6) lateral echo (marked; 7, nonexistent; 5) 7) width/depth ratio (1.5> 1, 1.0-1.5; 7, 1.0< ; 4). Uncommon breast cancer show benign nature on mammogram, but malignant nature on ultrasonogram (especially boundary echo, internal echo, width/depth ratio)