Background: Postoperative Endophthalmitis is a rare complication after intraocular surgeries. However, it remains one of the most devastating complications following cataract surgery because of its poor prognosis. We describe the effects of antibiotic prophylaxis on the incidence of postoperative endophthalmitis after cataract surgery, particularly phacoemulsification. Aim of the work: To identify risk factors of acute endophthalmitis and describe the effects of antibiotic prophylaxis on the incidence of postoperative endophthalmitis after phacoemulsification surgery. Methods: A prospective randomized cataract surgery study recruited 300 patients;150 patients who received just intracameral vigamox at the end of surgery without topical antibiotics before surgery and 150 patients who received both intracameral vigamoxas well as topical perioperative vigamox which either just half an hour before surgery or three days preceding surgery. We took a conjunctival swab before and after vigamox administration in order to detect the type of conjunctival flora in the Libyan population as well as the effect of the vigamox on the conjunctival flora by using Phoenix-BD machine. In total we collected 166 specimens (83 patients). Results: In all groups no acute post-operative endophthalmitis was reported. Conclusions: The study was based on intracameral Moxifloxacin at the end of surgery with and without topical antibiotics drops administration. The incidence of postcataract endophthalmitis was not reported in our study after using intracameral antibiotics, as it seems to be effective in preventing endophthalmitis after cataract surgery.