Objectives: The purpose of this study was to assess the effect on tooth sensitivity when potassium nitrate and fluoride were added to a 10% carbamide peroxide bleaching gel. Method and materials: Seventeen maxillary and four mandibular arches were bleached using the at-home bleaching technique. The bleaching treatment consisted of the simultaneous use of a 10% carbamide peroxide gel containing 3% potassium nitrate wt/vol and 0.11 fluoride ion wt/vol on one side of the midline and a 10% carbamide peroxide gel only (control) on the other side of the midline for 14 nights. A visual analog scale for each side of the dental arch was used by the patients to assess tooth sensitivity and tooth whitening. Preoperative and postoperative photographs were also taken. Results: The addition of potassium nitrate and fluoride significantly decreased the total tooth sensitivity reported by the patients. The addition did not significantly change the whitening efficacy of the carbamide peroxide bleach. Conclusion: A 10% carbamide peroxide bleaching gel containing potassium nitrate and fluoride produced less tooth sensitivity than did the control bleaching gel during a 2-week at-home bleaching treatment.