A radiator core support structure is a member to be mounted on a front portion of a vehicle body for supporting a radiator. The radiator core support structure comprises an upper elongate member made of metal, a lower elongate member made of metal and a hood lock stay portion made of molded plastic. The hood lock stay portion has an upper end integrally connected to the upper elongate member and a lower end that is shaped to grip an intermediate portion of the lower elongate member. The connection between the hood lock stay portion and each of the upper and lower elongate members is integrally carried out by injection molding.