The title compounds were prepared by induction levitation melting of the elemental components and subsequent annealing. UMnGe (Pnma, a = 686.12(9), b = 425.49(6) and c = 736.5(1) pm) adopts the orthorhombic structure of TiNiSi and U 2 Mn 3 Ge (P6 3 /mmc, a = 524.3(2) and c = 799.2(3) pm) possesses the hexagonal Mg 2 Cu 3 Si-type structure (ordered variant of the hexagonal Laves phase MgZn 2 ). Both structures were refined from X-ray powder data to residuals of R I = 0.021 and 0.014 for UMnGe and U 2 Mn 3 Ge, respectively. The manganese and germanium atoms in UMnGe build up a three-dimensional [MnGe] network of ordered Mn 3 Ge 3 hexagons with Mn–Ge distances ranging from 248 to 259 pm. The uranium atoms are coordinated by two tilted Mn 3 Ge 3 hexagons. The manganese atoms in U 2 Mn 3 Ge build up Kagomé networks with 252 and 272 pm Mn–Mn distances which are connected via the germanium atoms (254 pm Mn–Ge) to a three-dimensional network. A remarkable feature of the U 2 Mn 3 Ge structure is a short U–U distance of 278 pm between adjacent cavities of the [Mn 3 Ge] network. From DFT based electronic structure calculations both germanides are found more cohesive than the Laves phase UMn 2 , thus underpinning the substantial role of Mn–Ge bonding. Calculations for both germanides show ferrimagnetic ground states with antiparallel spin alignments between U and Mn. The valence bands show bonding characteristics for interactions of atoms of different chemical natures and significant Mn–Mn bonding in U 2 Mn 3 Ge. Preliminary investigation of UMnGe by magnetization measurements confirms an antiferromagnetic arrangement below T N = 240 K.