Objective. To study sonographic and histological features of chronic endometritis (CE) with normal and thin endometrium during two schemes of treatment. Material and methods. The study included 240 women (27.0±2.9 years) with CE who were treated with the help of vitamin- and physiotherapy (1st schema) and in combination with peloids (2nd schema) of Karachi-lake (Novosibirsk region). Ultrasound studies according with M.N. Bulanov’s CE scale scores and endometrial pipelle-biopsies were performed in the proliferative phase before and after treatment. Immunohistochemical (IHC) study of 81 cases was performed concerning the expression of CD138-positive plasma cells and CD20-positive B-lymphocytes. Results. Before the treatment in all clinical cases the sum of points on the quantitative ultrasound study was ≥4; after treatment, this score was preserved in 167 of 240 women, of whom 80 with normal endometrium (the 1st and 2nd groups) and 87 cases with «thin» endometrium (the 3rd and 4th groups); it means that women with normal and «thin» endometrium were characterized by marked regress of CE ultrasound symptoms (p<0.0001). The sum of points on the ultrasound ≥4 and a lack of histological endometrial markers of CE were considered as the reference for the implementation of IHC study for CD138 and/or CD20 molecular markers. Diagnostic informative value of the ultrasound point scale estimation of CE was the largest in the 1st group with the sensitivity 93.33%, accuracy 73.58%, and specificity 28.21%. Conclusions. It was confirmed the diagnostic value and reproducibility of M.N.Bulanov’s scoring CE ultrasound evaluation of the endometrium in women with CE during the proliferative phase. The method is highly sensitive (93%) in reproductive-age women with normal endometrial thickness. We have been proposed referencies for histological examination of the endometrium in patients with CE. It is necessary to continue the study on a larger number of clinical cases.