Objectives To evaluate the postoperative sensitivity of restorations with self-adhesive resin composite (SAC) (Vertise Flow (VER)/Kerr) compared with conventional resin composite with self-etching adhesive (Filtek Z250 (Z250)/3M ESPE; Clearfil SE Bond (CSEB)/Kuraray). Materials and methods A randomized, controlled, double-blind, split-mouth, two-arm clinical trial was conducted. Twenty-seven volunteers with third molars indicated for extraction received two deep class I restorations, one with each material. Postoperative sensitivity was measured at 24 h and 15 or 30 days after the restorative procedures using a visual analog scale (VAS). When present, information on the characteristics of the pain was also collected. The data were submitted to the McNemar test (alpha = 0.05). Results Regardless of the time intervals, the postoperative sensitivity was observed in 52% and 48% of the CSEB and VERT groups, respectively (p = 1.000). When the evaluation periods were analyzed, the 15-day evaluation presented the highest occurrence of pain, but of mild intensity, in both groups. All patients with sensitivity reported that the pain was localized and of short duration. Conclusion Self-adhesive resin composite Vertise Flow and conventional resin composite with a self-etching bonding agent promoted similar response regarding postoperative sensitivity in deep class I cavities. When postoperative sensitivity was present, mild pain was observed, especially after 15 days of the restorative procedure, which decreased over time.