ABSTRACT <p>This paper considers an algorithm for numerical solution of a one-dimensional inverse magnetotelluric sounding problem. The algorithm is based on a special type of algebraic equation which is called a pseudo-quadratic equation. The inverse problem is considered in three variants: 1) for media with fixed geometry; 2) for media with fixed geoelectrical properties; 3) general case. Additionally, an algorithm is proposed for input data processing which provides the existence of a solution to the inverse problem. Numerical experiments realized on test media with different sets of parameters are carried out to study and illustrate the efficiency of the algorithms.</p>