In the present work, the giant stress-impedance effect in Fe73.5CuNb3Si13.5B9 and Fe73.5CuNb2VSi13.5B9 amorphous ribbons was reported. The stress-impedance DeltaZ/Z(0) decreases with increasing ac frequency from 100 kHz to 20 MHz. When tensile stresses are applied perpendicular to the Earth's field, the value of stress-impedance DeltaZ/Z(0) at 100 kHz can reach -9.9% under a stress of 24.6 MPa for Fe73.5CuNb3Si13.5B9 ribbon, and -22.4% under a stress of 84.8 MPa for Fe73.5CuNb2VSi13.5B9 ribbon. The stress-impedance effect becomes small when tensile stresses are applied parallel to the Earth's field. The stress-impedance effect may be connected with the variation of the magnetic domain and permeability under application of stresses. (C) 2003 Elsevier Science B.V. All rights reserved.