We examine the problem of interpreting the direct measurement of the polarization sense for HF plasma waves, in a cold and collisionless magnetoplasma when two propagation modes are simultaneously present. Two types of propagation mode estimators are considered. The first, generally more sensitive to quasi-parallel waves, consists in the determination of the signs of cross-spectra between two electric or two magnetic wave field components, both perpendicular to each other and B0. The second, more sensitive to quasi-perpendicular waves, is obtained by testing the ratio of the parallel to the perpendicular energy, against physical thresholds. Interpretations of the results are shown to be a function of the wave and plasma parameters. Applications performed on synthetic data constructed from two propagation mode models with different wave distribution functions (WDF) are presented. They show that the combination of the different propagation mode estimators often enables us to point out the presence of the two modes. Moreover, when the WDFs of the two modes are very different and when the wave frequency is far from the characteristic frequencies of the medium, the main propagation properties of each mode may be derived. ¿ American Geophysical Union 1989