Objective: Tonsillectomy is one of the most common surgical procedures performed at ear, nose, and throat clinics. Chronic recurrent tonsillitis, obstructive tonsillitis, and halitosis are among the most common indications for surgery. Determining whether the infection is chronic and the patient's annual number of infections are important in estimating the necessity for surgery to be performed due to infectious causes. Red blood cell distribution width (RDW) is a numerical value present in normal complete blood count that provides information about erythrocytes and their dimensions. Studies in recent years have shown that RDW increases in chronic infections, hypoxia, and oxidative stress. This study investigated the changes in RDW in patients with chronic tonsillitis and the effect tonsillectomy has on this value by comparing RDW between patients scheduled for tonsillectomy and normal population and examining preoperative and postoperative changes in RDW.