Aerating system for the runner of a hydraulic turbine, the runner comprising a plurality of blades, such that inter-blade canals are configured between each pair of blades for the admission of air in the water flow circulating through the hydraulic turbine, such that the aerating system comprises at least one hydrofoil located in the inter-blade canal of the runner contacting the pair of blades configuring the inter-blade canal where the hydrofoil is located, such that the hydrofoil has a non-axis symmetrical profile, and such that at least one of the blades in contact with the hydrofoil comprises an aerating canal delivering air to the hydrofoil.