A cathode body for a rotating cylindrical magnetron wherein the magnetron provides a sputtering zone extending along the length of the cathode body and circumferentially along a relatively narrow region thereof. The cathode body includes an elongated tubular member having a target material at the outer surface thereof. A collar of electrically-conductive material is located at at least one end of the tubular member, and extends along the tubular member from that one end into the erosion zone. A sleeve of electrically-conductive material may extend circumferentially around the collar.