Objective: Tonsillectomy is one of the most common surgical procedures performed in Ear Nose Throat (ENT) practice. The tongue depressor, which is routinely used during tonsillectomy surgeries, may cause various complications by applying high pressure to the patient›s tongue. In this study, we aimed to investigate the tongue edema caused by the pressure applied by the tongue depressor using ultrasonography (USG) in adult patients who underwent tonsillectomy. Material and Methods: Our study consisted of two groups, including patients between the ages of 18-40. The patients in the study group (n = 31) were composed of patients who underwent tonsillectomy surgeries in the ENT clinic. The patients in the control group (n = 30) were composed of patients who were operated on for a reason other than tonsillectomy under general anesthesia, no pressure was applied on the tongue during surgery, and the duration of general anesthesia was close to the duration of tonsillectomy surgeries. Submental coronal plane USG examination of the tongue area (TA) was performed twice for each patient. The first tongue area examination (TA1) was performed immediately after intubation but before inserting the tongue depressor in the tonsillectomy group. The second tongue area examination (TA2) was performed at the end of the tonsillectomy surgery, after removal of the tongue depressor just before extubation. In the control group, the first tongue area examination (TA1) was performed immediately after intubation, and the second tongue area examination (TA2) was performed at the end of the operation just before extubation. Tongue edema, which is thought to occur due to the high pressure applied by the tongue depressor during tonsillectomy surgeries, was calculated by the difference in tongue areas (i.e., TA2-TA1). Results: The groups were similar in terms of demographic data and general anesthesia duration. When the mean TA1 values were taken into account between the tonsillectomy (3.93 ± 1.29 cm2) and control (3.80 ± 1.20 cm2) groups, no significant difference was found (p = 0.212). The mean TA2 value of the tonsillectomy group (4.63 ± 0.28 cm2) was greater than the control group’s TA2 value (3.91 ± 0.23 cm2) and was significantly different (p = 0.000). In addition, the mean tongue edema value of the tonsillectomy group (0.90 ± 0.26 cm2) was greater than the control group (0.11 ± 0.07 cm2) and was significantly different (p = 0.000). Conclusion: The tongue depressor used caused tongue edema in tonsillectomy surgeries in adult patients. This tongue edema appears to be the result of the pressure exerted by the tongue depressor. This study is the first to show the possible role of USG in determining tongue edema due to tongue depressor in adult patients undergoing tonsillectomy.