Purpose: To evaluate fluorescein angiography (FA) in eyes with aggressive posterior retinopathy of prematurity (AP-ROP). Design: Retrospective, nonrandomized case series. Participants: Three patients (6 eyes) with AP-ROP. Methods: Three patients (6 eyes) diagnosed with AP-ROP during ROP screening between July 2007 and July 2008 were included in this study. Fundus photographs and FA were obtained before and after laser and surgical treatment using a wide-field digital pediatric imaging system. Main Outcome Measures: Fluorescein angiography and fundus photographs. Results: At the initial stage of AP-ROP, FA showed vascular abnormalities, including capillary nonperfusion throughout the vascularized retina, shunting in the vascularized retina, a circumferential demarcation line, and limited vessel development, which was difficult to identify only by ophthalmoscopy. After treatment, FA showed poorly developed retinal vessels, including 4 small major vessels without an arcade pattern, small macular vessels, an inhomogeneous capillary bed, and absence of a capillary-free zone in the fovea. Conclusions: Capillary bed loss throughout the vascularized posterior retina is characteristic of AP-ROP and may exacerbate retinopathy. Financial Disclosure(s): The authors have no proprietary or commercial interest in any of the materials discussed in this article. Ophthalmology 2009; 116:1377-1382 (C) 2009 by the American Academy of Ophthalmology.