Difficult tracheal intubation (DI) is more common in thyroid than in other surgical branches due to thyromegaly. Proper preoperative airway evaluation is necessary in order to reduce the potential numerous complications. The study examined the incidence of DI in thyroid surgery and the influence of tracheal dislocation and other risk factors on DI. A prospective study was conducted on 2379 patients who underwent thyroidectomy at the Center for Endocrine Surgery, Clinical Center of Serbia, from 2007 to 2012. Patients were divided into groups with (n = 162) and without DI (n = 2217). Besides tracheal dislocation, another 13 risk factors contained in 13 screening tests and three additional factors of gender, age and diagnosis were defined. The incidence of DI in our study was 6.81%. The presence of tracheal dislocation was statistically significant, but not an independent predictor of DI. The diagnosis, large circumference and small neck length, previous DI, recessive mandible, tooth characteristics and oral anomalies were the most significant and independent predictors of DI. Neck circumference and small neck length had highest sensitivity. Previous DI had highest specificity. Thyromegaly, if causing tracheal dislocation and/or stenosis, represents a significant DI predictor, not individually, but in combination with other factors.