This article contains the following results of research the diagnosis of genital endometriosis of uterine preparations by the methods of polarization- phase Muller- matrix introscopy.The aim of the study. To estimate the eff ectiveness of diff erential diagnosis of genital endometriosis using polarization- phase Muller- matrix introscopy of histological sections of endometrial biopsy.Material and methods. Two groups of samples were studied:● biopsy of «healthy» uterine tissue obtained during diagnostic hysteroscopy – «control group 1.1» – 68 samples;● biopsy of uterine tissue with genital endometriosis – «experimental group 1.2» – 59 samples.Histological sections were made according to the standard technique on a microtome with rapid freezing. Research results. The analysis of the obtained statistical analysis data revealed the adequacy of the prognostic variant of changes in the polycrystalline structure of histological sections of endometrial biopsy. For patients with genital endometriosis, there is a signifi cant increase in linear birefringence.Diagnostic markers of this pathological process are an increase in the average value and dispersion of linear birefringence. The values of asymmetry and kurtosis, on the contrary, decrease.Statistical confi rmation of this is a statistically signifi cant diff erence (pi=1;2;3;4<0.05) between the values of the set of all central statistical moments of the 1st-4th orders, characterize the distributions of the PLD value of histological sections of endometrial biopsy for cases of conditional norm (control group 1.1) and genital endometriosis (experimental group 1.2).Conclusions. Therefore, the conducted set of studies using polarization- phase Muller- matrix introscopy of histological sections of endometrial biopsy revealed a high (up to 100 %) eff ectiveness of diff erential diagnosis of genital endometriosis. Therefore, it is relevant to study the diagnostic capabilities of this technique for more easily accessible objects – biological fl uids.