Background: Fiber reinforcement of conventional dental composites is introduced with the aim of enhancing their physical and mechanical properties and increasing their resistance to fracture. Aim: To compare the fracture resistance of class II MOD cavities restored with Filtek z350 composite with and without dentapreg fibre inserts on premolars. Materials and method: Forty non-carious permanent human maxillary premolar teeth were taken. Class II MOD cavities were prepared and divided into two groups 1) Group 1: teeth with class II MOD cavities restored with Filtek z350 composite using horizontal incremental technique. 2) Group 2: teeth with class II MOD cavities restored with Filtek z350 composite and dentapregfiber inserts using horizontal incremental technique. Then fracture resistance test was done using universal testing machine. Data analysis was done by applying Independent Sample t test. Results: Mean Fracture Resistance of teeth in Group II was higher than Mean Fracture Resistance of teeth in Group I (P < 0.05). Conclusion: Insertion of Dentapregfibers under composite restoration significantly increased the fracture resistance of the restored teeth.