In this work, Bi 2 Sr 2 CaCu 2-x Co x O y (x =0.0, 0.05, 0.10, and 0.25) textured superconductors were prepared by a LFZ melting technique. In all cases, the powder X-ray diffraction patterns of samples show that Bi-2212 phase is the major one. All samples have good oriented structure, which is a typical picture for superconductors prepared by LFZ method.Magnetization hysteresis loops, made for all samples at two different temperatures, showed that the loops become narrower with increasing temperature and doping levels. In addition, the effect of Co doping on the critical current density, J C , of Bi 2 Sr 2 CaCu 2-x Co x O y has been estimated from hysteresis loop measurement by using Bean's model. The increase of Co amount in Bi 2 Sr 2 CaCu 2-x Co x O y structure significantly decreases the critical current density, showing worse connectivity of the grains. All the results indicate that Co substitution for Cu produces the deterioration on the superconducting properties, compared with the undoped samples.