An inverse analysis is presented for simultaneous estimation of optical thickness, single scattering albedo and the coefficients of phase function for an anisotropic scattering plane-parallel medium. The Levenberg-Marquardt method of minimization is used to solve the resulting nonlinear system of algebraic equations. Forward and backward scattering phase functions are considered, and the effects of the magnitudes of single scattering albedo and optical thickness on the accuracy of the estimations are examined. The confidence bounds are established for the estimated values of the single scattering albedo, the optical thickness and the coefficients of the phase function.