A new iterative method based on an exact gradient search for inverse scattering problems is developed. In this scheme the two unknowns (the electric field and the electrical parameter within the object) are solved simultaneously. The bilinear property of the coupled integral equations is employed to drive the gradient of the residual ∇&PHgr;. The exact gradient formulation allows one to perform an efficient line search for the solution. Some numerical results based on two-dimensional inverse scattering problems are presented to demonstrate the efficiency of the algorithm. ¿ American Geophysical Union 1994