In order to develop an effective means to treat P. aeruginosa infections, we have purified P. aeruginosa outer membrane proteins (OMPs)-specific human IgG antibody. In this study, we investigated the protective activity of the purified anti-OMPs IgC against P. aeruginosa infection in a rabbit endophthalmitis model. Rabbits were inoculated by an intravitreal injection with P. aeruginosa, and treated with a single dose of 1 mg anti-P. aeruginosa OMPs IgG. All the control rabbits predominantly developed edematous responses and opacity in the eyes, but the rabbits treated with the antibody showed only very limited degree of edema. Aliquots of the vitreous humor were extracted and analyzed for the number of viable bacteria and endotoxin level. The results showed that the anti-OMPs IgC significantly reduced the bacterial count compared with the control group, and that the endotoxin level of the vitreous from the IgG-treated rabbits was more than 70-fold lower 6 h after the administration than the control animals. These data suggested that the anti-P. aeruginosa OMPs IgG is effective in inhibiting the bacterial growth and thereby in reducing endotoxin levels in the vitreous, warranting further development of the anti-P. aeruginosa OMPs IgG as a therapeutic means for treating Pseudomonas endophthalmitis.