The formation range and zero-magnetostrictive compositions for Co-TM-Zr (TM = V, Cr, Mo or W) amorphous alloys have been examined. And their low field magnetic properties also have been measured. The addition of TM elements extends the zirconium content forming amorphous single phase for Co-Zr system to the range of 5–18 at%. The zero-magnetostriction lines for all systems except for Co-W-Zr are located in the range of 7–15 at% TM. The crystallization temperature, Tx, for the alloys with Co less than 83 at% exceeds 500 °C, which is significantly higher than that for Co-Fe-Metalloids alloys. Increment of Co content in this type zero-magnetostrictive alloys raises Curie temperature, Tc, and increases saturation magnetization monotonically, but decreases Tx slightly. The present alloys containing Co less than 82 at% exhibit excellent low field magnetic properties such as coercivity, Hc = 7 mOe in static field and effective permeability, μe(1 kHz, 10 mOe) = 34,800 for annealed Co77Cr11.7Zr11.3 amorphous alloy.