The effects of nitrogenation on the magnetic properties of Sm₂(Fe_0.9M_0.1)₁₇C_1.6 (M=Ga, Cr) melt-spun ribbons were studied. The melt-spun amorphous ribbons were crystallized at above 550°C in forming TbCu₇ phase, and they were further transformed to Th₂Zn₁₇ phase above 680°C on heating. The nitrogenation at 550°C for 4 h enhances the magnetic properties of annealed ribbons. The Sm₂(Fe_0.9Cr_0.1)₁₇C_1.6 ribbon annealed at 650°C which consists of TbCu₇ phase, exhibits high (BH)_max, of 11.0 MGOe after nitrogenation. The Sm₂(Fe_0.9Cr_0.1)₁₇C_1.6 ribbon annealed at 725°C. which consists of Th₂Zn₁₇ phase, shows high coercivity of 19.0 kOe with (BH)_max, of 7.4 MGOe after nitrogenation.