A calcium ferro-aluminate with composition CaAl1.8Fe0.2O4 has been synthesized. The crystal structure of the phase was studied by X-ray single crystal diffraction and refined to an R1-index value of 0.033, for 1287 observed independent reflections, collected with graphite monochromatized MoKα-radiation. The compound crystallizes in the monoclinic space group P121/nl with Z = 12. Cell parameters were a = 8.758(1) Å, b = 8.112(1) Å, c = 15.311(1) Å, β = 90.21(1)°. The crystal structure is characterized by layers of six-membered tetrahedral rings of ditrigonal shape showing two different ring conformations of up (U) and down (D) pointing vertices: UUDUDD and UDUDUD, respectively. The stacking of layers comprises a three-dimensional framework containing channels that are occupied by the calcium cations. The structure is isotypic with CaAl2O4, the major compound of calcium aluminate cements.