Mn-doped 0.98K(0.5)Na(0.5)NbO(3)-0.02BiScO(3) (0.98KNN-0.02BS) lead-free piezoelectric ceramics have been prepared by a conventional sintering technique and the effects of Mn doping on the phase structure and piezoelectric properties of the ceramics have been studied. Our results reveal that a small amount of Mn can improve the densification of the ceramics effectively. Because of the high densification, fine grain, and Mn doping effects, the piezoelectric and dielectric properties of the ceramics are improved considerably. Very good piezoelectric and dielectric properties of d(33)=288 pC/N, k(p)=0.46, epsilon(r)=1591, and T-C=328 degrees C were obtained for the 0.98KNN-0.02BS ceramics doped with 0.8 mol% Mn. Therefore, the 0.98KNN-0.02BS ceramics containing a small amount of Mn are a good candidate material for lead-free piezoelectric ceramics.