U3Cu4Ge4 which crystallizes in the orthorhombic Gd3Cu4Ge4-type structure, orders ferromagnetically below TC = 71(1) K. This ternary germanide was investigated by neutron powder diffraction. The ferromagnetic transition is observed by this study at TC = 69(2) K. The magnetic structure is described by U-moments equal to 1.71(1) μB and all parallel to the a-axis. In other words, the two inequivalent U-atoms (U1 and U2) carry the same moment. This structure is discussed in relation to those previously reported for other germanides as UGe2, UCu2Ge2 and UCuGe which exhibit some structural relationship.