Purpose: To study the clinical characteristics, therapeutic efficacy and investigate prognostic factors of endogenous endophthalmitis.Methods: Twenty-eight cases (28 eyes) of endogenous endophthalmitis were surveyed retrospectively. The clinical characteristics, primary infection foci, predisposing systemic disease, complications, pathogens examination, therapeutic options and efficacy were analysed.Results: The endogenous endophthalmitis occurred more frequently in the right eye than in the left one. The respiratory tract was the most common primary foci. The positive rate of pathogens culture was higher in vitreous sample than that in other tissues. Cataract and retinal detachment were the common complications. The visual improvement and infection control were achieved in 13 eyes (46.43%). These 13 patients received treatment (3.77±2.49) days after onset of endophthalmitis being much earlier than that of others [ ( 10.13 ±4.98)days, P=0.002]. The prognosis was relevant to the type of the disease. The anterior segment inflammation type (anterior type) had better prognosis than posterior segment inflammation type(posterior type) and that of inflammation in both parts(mix type) (P ＜0.05). There were no significant relation between the prognosis and the age, predisposing systemic disease, vitreous antibiotic injection and vitrectomy (P ＞ 0.05).Conclusions: Endogenous endophthalmitis is a vital ocular emergency. Early diagnosis and effective treatment combination with systemic and local antibiotics are of significant value. The anterior type is prone to have better outcome than the others.