The purpose of this study was to analyze the causes of false results in the ultrasound (US) and sonoelastography (SEG) examination of non-palpable and palpable lesions of the breast. The efficacy of diagnosis of non-palpable and palpable lesions by US and SEG was compared. 211 women with histologically confirmed focal breast lesions (146 non-palpable and 65 palpable) were included in the group. Women had a mean age of 52,0±13,6 years. The diameter of non-palpable lesions was less than 2 cm. Local mastopathy and medullar carcinoma were the reason of false results in most US. SEG allowed differentiating of these lesions. We found that SEG increased the specificity of diagnostics of non-palpable breast lesions by 19%.