To evaluate the bleaching efficacy of at-home carbamide peroxide (CP) gels in two concentrations, containing or not a desensitizing agent. Forty incisors were divided into four groups (n=10), according to gel concentrations (10% or 22%), and presence or not of 3% potassium nitrate in the gel. A thin layer of gel was applied to the buccal surface of each tooth for 2h/day for 4 weeks. Bleaching efficacy was measured using a spectrophotometer, and ?E*ab, ?E00 and ?WID were calculated. Measurements were performed at baseline, 7, 14, 21, 28, and 35 days following the first gel application. Data were analyzed by two-way RM-ANOVA and Tukey?s test (?=0.05). Regarding gel concentration or potassium nitrate inclusion, both gels resulted in color change above the perceptibility thresholds, which were similar between gels. Regarding time, significant differences were observed between color change values at 7 days and other time periods. ?WID ranged from 3.8 to 9.6. Significant moderate to strong positive correlation was observed among the parameters. Nor the CP concentration, neither the inclusion of potassium nitrate in the gel, had influence on bleaching efficacy. All gels were effective and showed good results from the first weeks? application.