The frontier of quantum chaos emerging from mesoscopic quantum transport is reviewed. A singlestadium billiard and antidot superlattices with square and triangular arrays are chosen as prototype systems. The semiclassical theory plays an important role in interpreting the experimental issue. The area distribution of backscattering orbits and the bifurcation of periodic orbits are shown to affect the anomalousfluctuations in the magnetoresistivity. The optical realization of quantum chaos is also discussed.