The effects of Cr substitution on the formation, structure and magnetic properties of Sm 2 (Fe, Cr) 1 7 C x compounds have been systematically studied on arc-melted and melt-spun samples using XRD, TEM and magnetic measurements. It has been found that Cr substitution is an effective way to form the Sm 2 (Fe, Cr) 1 7 C x carbides. The minimum Cr amount for Sm 2 Fe 1 7 - y Cr y C 2 to form an almost single 2:17 phase is around y = 2 and the maximum carbon amount for Sm 2 Fe 1 5 Cr 2 C x to remain in a single 2:17 structure is around x = 2. Magnetic measurements reveal that the Cr substituted Sm 2 (Fe, Cr) 1 7 C x carbides have a strong uniaxial magnetocrystalline anisotropy with anisotropy fields higher than 90 kOe obtained in Sm 2 Fe 1 5 Cr 2 C 2 and Sm 2 Fe 1 4 Cr 3 C 2 carbides. However, both the Curie temperature and the magnetization are found to decrease with Cr substitution. High coercivity can be obtained in Sm 2 (Fe, Cr) 1 7 C x ribbons produced by the melt-spinning technique. The highest coercivity of 13.2 kOe has been obtained in Sm 2 Fe 1 5 Cr 2 C 2 ribbons spun at 52 m/s and annealed at 750°C for 20 min.