Purpose: to investigate the role of vitreous body changes in the pathogenesis of aggressive posterior retinopathy of prematurity. Material and methods. The study included 60 children with stage 4-5 retinopathy of prematurity demonstrating either classical or aggressive posterior form of progression. In all cases vitreous samples for laboratory testing were taken during surgery. Results. The study showed that aggressive posterior retinopathy of prematurity is associated with more significant metabolic changes in comparison with classical form of the disease. The degree of biochemical imbalance of the vitreous appeared directly related to the stage of the disease, which was determined by the type and extent of retinal detachment. Volcano-shaped retinal detachment with intensive exudation within the posterior eye segment is considered the most severe variant of aggressive posterior retinopathy of prematurity. Conclusion. Aggressive posterior retinopathy of prematurity is characterized by substantial disturbance of metabolism of the vitreous body, which contributes to exudation and proliferation, thus aggravating the course of the disease and worsening the prognosis.