A magnetic recording medium having a high ratio of the residual magnetization (Br) to the saturation magnetization (Bm) and decreased voids, which has a magnetizable layer of magnetic particles which are dispersed in a binder: a polyester or polyurethane having a metal sulfonate group of 10 to 1,000 equivalents/10.sup.6 g of the polymer, preferably a polyester having a reduced viscosity of 0.2 or more and having a metal sulfonate group of 20 to 300 equivalents/10.sup.6 g of the polyester; a polyester having a reduced viscosity of less than 0.2 and having a metal sulfonate group of 20 to 500 equivalents/10.sup.6 g of the polyester; or a polyurethane having a metal sulfonate group of 20 to 400 equivalents/10.sup.6 g of the polyurethane. Said magnetic recording medium is particularly suitable for an electronic computer tape and video tape.