Provided are slurry for polishing cobalt and a substrate polishing method. The slurry includes an abrasive configured to perform the polishing, the abrasive comprising zirconium oxide particles, a dispersing agent configured to disperse the abrasive, and a polishing accelerator configured to accelerate the polishing. The polishing accelerator includes an organic acid containing an amine group and a carboxylic group. According to the slurry in accordance with an exemplary embodiment, a polishing rate of the cobalt may increases without using an oxidizing agent, and local corrosion defects on a surface of the cobalt may be suppressed.