Background & objective: Difficult intubation remains a risk for patients undergoing general anesthesia (GA) or mechanical ventilation in an intensive care unit (ICU). Macroglossia is a known factor for difficult intubation. But it is not routine to assess the tongue size to predict difficult intubation. Studies are found deficient in comparing usefulness of measuring thyromental distance and the tongue thickness (TT) measured by ultrasonography to estimate difficult intubation. We compared tongue thickness measured by ultrasonography and thyromental distance as a means to anticipate difficult intubation. Methodology: A convenient sample of 60 patients; 32 males and 28 females, who were undergoing elective surgery with GA were included. Thyro-mental distance (TMD), along with tongue thickness (TT) were measured consecutively in each patient in a transitional room. After induction of GA, Cormack Lehane (CL) score was assessed for all patients to detect difficult intubation. Results: Thyro-mental distance was significantly reduced in patients with difficult intubation, while the reverse was in the measurement of tongue thickness; where patients with difficult intubation had significantly a greater TT than those with no difficult intubation. TT measurement had significantly higher sensitivity and specificity (38%, and 96% respectively; P = 0.002) than thyro-mental distance in the detection of difficult intubation. Conclusion: In this study we demonstrated that there was statistically significant inverse relationship of thyro-mental distance on CL, and statistically significant direct relationship of tongue thickness on CL. The results showed that tongue thickness was more effective to detect difficult intubation. Abbreviations: CL - Cormack Lehane; TMD - Thyro-mental distance; TT - Tongue thickness; Keywords: Tongue Thickness; Thyromental Distance; Difficult Intubation Citation: Kadhim AB, Hamid GR. A comparative study between tongue thickness measured by ultrasonography and thyromental distance in anticipation of difficult intubation. Anaesth. pain intensive care 2024;28(3):431−435; DOI: 10.35975/apic.v28i3.2465 Received: March 16, 2024; Reviewed: March 29, 2024; Accepted: March 31, 2024