The aim of this study was to evaluate the effect of a novel phthalimidoperoxycaproic acid (PAP) and carbamide peroxide-based bleaching gels on shear bond strength between enamel and resin composite used to bond orthodontic brackets. Materials and Methods: Fifty four human premolars were selected and divided into three equal groups (N=18); Group I (control): unbleached teeth (C), Group II: received carbamide peroxide-based bleaching material (CP) and Group III: received PAP-based bleaching material (PAP). Each group was further subdivided into two equal subgroups according to time of bonding of the orthodontic brackets either immediately after bleaching procedure (IB) or 14 days after bleaching procedure (DB) (n=9/subgroup). According to their assigned subgroups, labial enamel surfaces of teeth were bleached, embedded in acrylic resin blocks and orthodontic brackets were bonded using Transbond XT light cure resin composite (3 M Unitek, Monrovia, CA, USA). Teeth were mounted in a universal testing machine and shear bond strength were measured in MPa. Data were statistically analyzed by two-way ANOVA and Tukey's post hoc significance difference test were used to analyze the data. Results: Two-way ANOVA showed that the two variables in this study had a statistically significant effect on enamel/resin composite shear bond strength, also there was an interaction between the two tested variables. Conclusions: PAP-based bleaching agents may present a safe alternative to free radical-based bleaching agents. Delayed bonding may play a role in improving bonding to bleached enamel.