In this paper, we present a Born Iterative Method for imaging optical properties of turbid media using frequency-domain data. In each iteration, the incident field and the associated weight matrix are first recalculated based on the previous reconstructed image. A new estimate is then obtained by a multigrid finite difference method. The inversion is carried out through a Tikhonov regularized optimization process using the conjugate gradient descent. Using this method, the distribution of the complex wavenumbers in a test medium is first reconstructed, from which the absorption and scattering distributions are then derived. Simulation results have shown that this method can yield quantitatively quite accurate reconstruction even when a strong perturbation exists between the actual medium and an assumed homogeneous background medium, in which case the Born approximation cannot work well. Both full-angle and limited angle measurement schemes have been simulated to understand the effect of the location of detectors and sources.