The Dancoff correction factor (1 − C) for U238 resonance neutron capture was measured for cylindrical, 0.98 cm diameter fuel rods at lattice pitches of 1.81 cm and 1.44 cm. The rods were 1.3% U235, arranged in a hexagonal, H2O-moderated lattice. Measurements were done for three fuel materials: uranium metal, UO2 (density 10.5 gm/cm3), and UO2 (density 7.5 gm/cm3) according to the following method. The ratio of U238 epicadmium neutron capture per atom at rod surface to that at rod center, S/V, was measured, for each fuel composition, at both lattice pitches and in an isolated rod (i.e., no Dancoff interaction). The quantity R ≡ [(S − V)/V]lattice/[(S − V)/V]isolated rod was, within experimental error, the same for all three fuel materials at each lattice pitch. Furthermore, within experimental error, R was found to be equal to (1 − C), calculated at each lattice pitch from Dancoff's expression. This agreement was expected from an analysis of the experiment in terms of a current model of resonance capture which indicated that R equals (1 − C) multiplied by two factors: one accounting for lattice mutual shielding of capture at rod center, the other accounting for the effect on S/V of the resonance flux lethargy tilt (due to loss of neutrons by resonance capture). Approximate calculations of these two effects showed that each perturbs R by about 10% in the worst case. The effects oppose each other so that very closely R = 1 − C.