Cytomegalovirus (CMV) retinitis is characterized by alterations in retinal cell function and host responses to virus replication. The goal of this study was to evaluate the induction of cyclooxygenase-2 (COX-2) and prostaglandin (PGE) in CMV infected human retinal pigment epithelial (RPE) cells and to determine their effect on virus replication. CMV immediate early (IE) protein and COX-2 proteins were identified in RPE cells in retinal tissue sections from patients with CMV retinitis. COX-2 mRNA and protein were induced after CMV infection of human RPE cell cultures. CMV infection of RPE cells induced translocation of NF-kappaB from the cytoplasm to the nucleus. PGE1 and PGE2 were significantly (p<0.001) increased in human RPE cell cultures infected with CMV. Inhibition of CMV IE gene by antisense oligonucleotides abrogated induction of mRNA for COX-2 and protein synthesis of COX-2 and PGE2. PGE enhanced CMV plaque formation and real time PCR analysis revealed that PGE treatment significantly increased CMV DNA copy numbers. These studies demonstrate that when CMV replicates within human RPE cells, COX-2 induction augments virus replication via the PGE pathway. The induction of COX-2 and PGE during retinal CMV infection may augment virus replication and alter a variety of retinal physiological responses.