Statement of the problem: The effectiveness of minimally invasive endodontic treatments in managing necrotic pulp with apical periodontitis remains understudied. Aim of the study: This research aims to evaluate the outcomes of minimally invasive versus traditional root canal treatments in patients with necrotic pulp associated with apical periodontitis. Material and methods: sixty healthy patients of both genders aged from 20 to 50 years old suffering from necrotic pulp associated with apical periodontitis in their lower first molars with four root canals will be included in this study. The initial assessment will include a preoperative CBCT scan. Participants will be randomly assigned according to the type of endodontic treatment to two groups; a traditional treatment group (Trad); in which a traditional access cavity design and root canal preparation extending three sizes beyond the initial apical file using taper .04 rotary files will be accomplished and a minimally invasive group (MI) in which a conservative access cavity and a conservative root canal preparation up to #20/.04 will be performed. Both groups will receive an identical irrigation protocol during root canal instrumentation augmented with passive ultrasonic activation. Immediately following biomechanical preparation, the root canals will be filled with single cone obturation technique. Root canal disinfection will be evaluated using a culture method in which two bacterial samplings will be collected, one before and another after the biomechanical preparation. Patients will be monitored over 12 months, concluding with a follow-up CBCT scan to assess periapical healing. Data will be collected and statistically analyzed.