An inner door panel (30) for a vehicle side door that includes an integrated side impact beam (70) formed as part of the door in a die casting process. The inner door panel (30) includes an outer frame having a top rail (38), a bottom rail (40), an inner side rail (42) and an outer side rail (44) defining a central opening (34). The impact beam (70) includes a main beam portion (72), a first end support portion (74) and a second end support portion (78). The first end support portion is formed to the side rail (42) and the second end support portion (78) is formed to the outer side rail (44), where the main beam portion (72) extends across the opening (34).