Objective: to study the capabilities of ultrasonography (USG) in the primary and specifying diagnosis of cancer of the tongue and mouth floor. Material and methods. The investigation was conducted with the GE logiq 9, by using the following modes: B-mode; virtual convex scanning providing a wider field of view; pulsed wave (PW) Doppler, and color Doppler mapping (CDM). A total of 128 patients, including 54 (42.2%) with tumors of the mouth floor mucosa and 74 (57.8%) with those of the tongue, were examined. There were 92 (71.2%) men and 36 (28.8%) women; their mean age was 55 years. USG was performed to estimate tumor spread to anatomically important adjacent structures. The findings were compared with magnetic resonance imaging data. Results. In all cases, tumor masses of the tongue and mouth appeared echographically as infiltrative changes mainly of hypoechoic (99.2%), heterogeneous and/or slightly heterogeneous (61%) patterns with uneven (93.8%) and indistinct (95.3%) outlines. In other cases, the changes presented with nodular masses (4.7%); in these cases, their outline was distinct, in places uneven. CDM revealed that blood flow was increased in the majority of cases (72.3%). Blood flow in the tumor did not differ from the rate of that in healthy tissue in 3.3% of cases and it was absent in other cases (24.4%). Conclusion. USG makes it possible to visualize well changes in the oral mucosal tumore and to estimate its spread to important anatomic structures.