Endotracheal intubation is an important act in the practice of anesthesiology. Direct laryngoscopy is the most commonly used technique to accomplish this task. Airway characteristics predicting difficult intubation with direct laryngoscopy are well defined. Physical findings, such as Mallampati classification or measurements of the thyromental distance, mouth opening, and neck extension have been validated to help anticipate difficult situations. When direct laryngoscopy is strenuous, early conversion to an alternative technique might reduce the risk of airway compromise and associated morbidity.