BACKGROUNDEndodontically treated teeth are more susceptible to fracture as a result of increased brittleness and are weakened because of coronal destruction. Endodontically treated teeth with small or minimal cavities can be restored with direct composites in the presence of buccal and palatal cusp with intact marginal ridge. Bulk fill has minimal polymerisation shrinkage rate, curing depth of 4 mm, better bond strength and good physical properties. Other advantages include fewer void in the restorative material and lesser risk of contamination between layers. MATERIALS AND METHODSForty intact human upper premolars were selected for this study. In G1 to G4 standard class I cavity preparation with mesiodistal length of 4 mm and bucco-palatal width of 3 mm were done. A conservative endodontic access was done. All canals were prepared with Ni-Ti K files using a step-back technique. All teeth were obturated with gutta-percha. The teeth were randomly divided into four groups, G1 Tetric N Ceram bulk fill, G2 Filtek bulk fill, G3 Smart Dentin Replacement bulk fill and G4 Packable composite Filtek P60. RESULTSThere was a statistically significant effect on the fracture resistance of endodontically treated premolars with class I cavities using bulk fill composites (p < 0.05). CONCLUSIONBulk fill composite can be used as a final restoration in endodontically treated premolars with class I cavity, as it can also preserve sound tooth structure which can increase fracture resistance of the tooth.