Abstract: The magnetic field and beat-treatment dependences of the ultrasound velocities at constant magnetic field (CH) and at constant magnetic induction (c_B) and magnetomechanical coupling were investigated in Fe_62.5Co₆Ni_7.5Zr₆Cu₁Nb₂B₁₅ alloy strips in an as-quenched state and after annealing above the Curie temperature. After annealing above 350^oC (up to 390^oC) the magnetomechanical coupling coefficient (k) was three times higher than that for asquenched state (0.10-012), i.e. k = 0.32-0.37. The minimum values of the c_H (= 3.6 km/s) were observed after annealing in the temperature range from 350 to 390^oC at 75-100 A/m. There are equal or somewhat higher values of bias field for the minimum of the c_H than in some other iron-rich amorphous alloys. Effect de was very small for as-quenched samples. When the samples reached the magnetic saturation, the domain structure vanished and then the Hooke's law was valid, i.e. E_H = E_B = E, where E was then material constant, known as Young's modulus and then the ultrasound velocities are also material constant.