The reaction of the β-propiolactam-derived platinum(II) amidate complex [Pt{NC(O)CH₂CH₂}₂(PPh₃)₂]with uranyl nitrate gives the coordination complex [Pt{NC(O)CH₂CH₂}₂(PPh₃)₂].UO₂(NO₃)₂, which was characterised by a single-crystal X-ray diffraction study. The lactam carbonyl groups are coordinated to the linear uranyl group, forming an eight-membered ring, with the uranium also having two bidentate nitrates, completing a hexagonal bipyramidal coordination geometry. The platinum and uranium coordination planes are almost perpendicular, at an angle of 85.4(1)°.