The structural and magnetic properties of compounds in the series Sm₂Fe₁₅Al₂C_x have been investigated by means of x-ray diffraction (XRD) and magnetization measurements. Samples with x=0, 0.5, 1.0, 1.5, and 2.0 were prepared by the arc-melting method. XRD patterns indicate that these carbides are single phase with a rhombohedral Th₂Zn₁₇-type structure, except for Sm₂Fe₁₅Al₂, which contains a few per cent of BCC alpha -Fe. The saturation magnetization for all samples is about 110 emu g^-1 and has a small dependence on C concentration. The Curie temperature T_c enhancement is about 190 K for x=1.5 compared with that of Sm₂Fe₁₇. All compounds exhibit an easy c-axis anisotropy at room temperature and the anisotropy field increases to about 110 kOe when x<or=1.5. The substitution of Al, like Ga and Si, is found to not only help the formation of high-C-concentration rare-earth-Fe compounds with 2:17-type structure, but also increase the anisotropy field.