DNA polymerase II of Escherichia coli, an alpha-like or group B polymerase, has been crystallized. The crystals are orthorhombic, space group P2(1)2(1)2, with cell dimensions a = 94.4 A, b = 118.2 A, c = 84.2 A and diffract to at least 3.0 A resolution. This is the first example of a group B polymerase to be crystallized.