A method for deburring a ceramic foundry core obtained by injecting a ceramic paste, the paste including a binder having a predetermined glass transition temperature, into a mold and having at least one surface portion with a surplus of material forming a burr to be eliminated. The method includes the following stages: a) disposing and attaching the molded, unfired foundry core onto a mounting; b) placing a milling tool, having an elongated shape with a helically cut edge, onto a tool holder; c) causing the tool to rotate around its axis and touching the milling tool to the surface portion to be deburred; and d) freezing the surface portion to be deburred such that the foundry core is maintained at a temperature lower than a glass transition temperature during the deburring operation.