X-ray phase analysis and microprobe analysis were employed in constructing the isothermal section of the Dy–Co–Si system at 870/1070 K. The isothermal section contains the known BaCd 11 -type DyCo 8.5 Si 2.5 , LaCo 9 Si 4 -type DyCo 9 Si 4 , CeGa 2 Al 2 -type DyCo 2 Si 2 , Lu 2 Co 3 Si 5 -type Dy 2 Co 3 Si 5 , TiNiSi-type DyCoSi, Hf 3 Ni 2 Si 3 -type Dy 3 Co 2 Si 3 , Sc 2 CoSi 2 -type Dy 2 CoSi 2 , CeNiSi 2 -type DyCo 1…0.75 Si 2 , Dy 3 Co 2.2 Si 1.8 -type Dy 3 Co 2.2 Si 1.8 and new CeCo 3 B 2 -type DyCo 3 Si 2 , CeNi 3 -type DyCo 2.56 Si 0.44 , La 3 Co 2 Sn 7 -type Dy 3 Co 2 Si 7 , BaNiSn 3 -type DyCoSi 3 ternary compounds and compounds with unknown type structure ∼DyCoSi 3 and ∼Dy 24 Co 14 Si 62 .The ternary solid solution based on the binary compounds of the Dy–Co system (excepting Dy 3 Co), AlB 2 -type DyCo 1.67 and ThSi 2 -type DySi 2 , were detected in the isothermal section at 870/1070 K. The other binary compounds of the Dy–Co–Si system do not show any visible solubility.The DyCo 2.56 Si 0.44 and Dy 3 Co 2 Si 3 phases show ferromagnetic ordering at 165 and 17 K. At 41 K DyCo 2.56 Si 0.44 demonstrates second magnetic transition. The Dy 3 Co 2 Si 7 has the Neel point 10 K.