Background: Resin-based composites (RBCs) are now considered as a material of choice restorative dental materials. The insertion of composite resins into the cavities demand adequate curing with light cure gun. The present study was conducted to assess depth of cure of bulk-fill composites. Materials & Methods: The present invitro study was conducted in the department of endodontics. It comprised of four RBC material-Tetric N-Ceram bulk fill (TNCBF), Tetric Evoflow bulk fill (TEFBF), surefil SDR bulk-fill (SDRBF) and fill-Up Dual cure bulk fill (FUDBF). Ethical clearance was obtained from institutional ethical committee. The surface hardness was measured on the top and the bottom by recording Vickers hardness number by Vickers hardness indenter. Results: The hardness value of 41.8, 39.7, 39.2 and 45.3 in group I, II, III and IV respectively at top. At bottom, it was 30.7, 32.5, 34.2 and 34.5 in group I, II, III and IV respectively. Bottom to top ratio was 0.71, 0.73, 0.82 and 0.85 in group I, II, III and IV respectively. Conclusion: Authors found that maximum bottom to top ratio hardness value was maximum with Surefil SDR bulk-fill and Fill-up dual cure bulk fill composite resins. Key words: Surefil SDR, Fill-up dual cure bulk fill composite, depth of cure