The crystal structure of CaMgGeO4 is described. CaMgGeO4, M(r) = 200.9, orthorhombic, Pnam, a = 11.285(5) Angstrom, b = 5.016(2) Angstrom, c = 6.435(2) Angstrom, V = 364.36 Angstrom(3), Dx = 3.664 Mg/m(3).lambda(MoKalpha)= 0.71069 Angstrom, F(000)= 384, room temperature, final R = 0.045 for 1752 observed reflections. The structure is isomorphous with CaMgSiO4 (monticellite).