A magnetic recording medium comprising a non-magnetic support, a magnetic layer, and an undercoat layer provided therebetween, and said undercoat layer comprising: (A) at least one resin selected from the group consisting of polyester resins having one or more hydroxyl groups and polyurethane resins having one or more hydroxyl groups; (B) a polyisocyanate compound (C) at least one compound selected from the group consisting of organometallic compounds and tertiary amine compounds; and (D) carbon black having an average single particle size of 50 .mu.m or smaller and an oil absorption of 100 g DBP/100 g or less; and having an (A)/(D) content ratio of 30/70 to 70/30, by weight, a (B) content of 15 to 50 wt. % based on component (A), and a (C) content of 0.5 to 5 wt. % based on component (A).