Fast direct planar full-wave electromagnetic analysis of microstrip structures embedded in multilayered medium is demonstrated. The impedance matrix of the Moment Method is stored in compressed format of a hierarchical matrix. The matrix equation is subsequently solved using hierarchical LU decomposition. Accuracy of analysis in a broad range of frequencies is demonstrated. Compression rate and accuracy of the computed reflection loss for a microstrip structure situated in multilayered media are presented as a function of tolerance in SVD of rank- deficient blocks of the hierarchical matrix.