Objective: To identify the most important variables that predict surgicaldifficulty and postoperative morbidity in lower third molar surgery.Method: A unilateral 100 impacted lower third molar teeth were surgicallyremoved under local anesthesia, and the review appointment was done within aweek of surgery. Preoperative predictor variables were categorized asdemographic, anatomic and operative variables. Evaluation of these variableswas done through a personal data, extra and intra oral examination, radiologicalexamination, while the postoperative morbidity pain, swelling and trismus wererecorded, then a statistical analysis was performed for all the variables.Results: Increased difficulty and postoperative morbidity related to increasedpatient’s age and gender, unfavorable tooth morphology, proximity to theinferior alveolar canal, three sided flap design and increasing the operative time.Conclusion: The anatomical and operative variables play an important role insurgical difficulty and postoperative morbidity in the removal of impactedmandibular third molars.