Introduction & Objective: Evidence is accumulating on the efficacy of non-operative management of blunt hepatic and splenic trauma as the treatment of choice in these patients. Materials & Methods: In this prospective study, our sample comprised of patients referred to the emergency department of Imam Hosein Hospital with blunt hepatic and splenic trauma confirmed by CT-scan and ultrasound. All of the hemodynamically stable patients, with no other indications for laparotomy were monitored in the ICU and managed non-operatively. The management plan changed accordingly in cases that non-operative plan failed. Results: In our subjects, 61(49.2%), 50(40.3%) and 13 (10.5%) had hepatic, splenic and concomitant blunt hepatic and splenic trauma, respectively. Non-operative management succeeded in 103 (83%); in the remaining 21 (17%) patients, older age and higher trauma grades were significantly associated with the failure of non-operative management. Concomitant trauma, particularly head trauma was only significantly associated with the failure of non-operative management in those with blunt splenic trauma. Conclusions: Non-operative management of the blunt hepatic and splenic trauma in hemodynamically stable patients is considered the treatment of choice, with high efficacy and low complications if managed successfully. Yet, due to considerable complications associated with the failure of non-operative treatment, independent prognostic factors that could predict unsuccessful management should be considered in advance by the surgical team. Important predictors of failure are older age, particularly above 55, concomitant trauma, especially to the head and higher grades of trauma.