Phase relations and the stability of crystallographic shear (CS) structure compounds (Cr,Fe) 2 Ti n؊2 O 2n؊1 in the system Fe 2 O 3 +Cr 2 O 3 +TiO 2 were investigated between 1000 and 13003C. The ternary comprises 5ve major solid solution series. These are as follows: an M 2 O 3 series; an M 3 O 5 series made up of two separate solid solution series=the 5rst an orthorhombic pseudobrookite M 3 O 5 solid solution and the second a monoclinic M 3 O 5 series based on the V 3 O 5 structure type; an M 4 O 7 series; and an M 5 O 9 series. These latter three series represent lower homologues (n ؍ 3, 4, and 5) of the (Cr,Fe) 2 Ti n؊2 O 2n؊1 CS compound series. Between adjacent M 3 O 5 and M 4 O 7 and M 4 O 7 and M 5 O 9 solid solutions, ordered intergrowths may occur. The stability and compositional limits of the solid solution series and intergrowth phases are dependent upon the temperature and Fe : Cr ratio. At high-TiO 2 contents, assemblages may contain either members of the Andersson phase series Cr 2 Ti n؊2 O 2n؊1 , a continuous CS structure series extending into the ternary, or a rutile-based solid solution. A comparison of results from this study with previously published phase relations has led to a revised version of the Fe 2 O 3 +Cr 2 O 3 +TiO 2 phase diagram.