Proliferative vitreoretinopathy (PVR) is a major complication of rhegmatogenous retinal detachment. Its pathogenesis remains poorly understood and the accurate nature of the growing cells on both surfaces of the detached retina has not been yet determined. We undertook an immunocytological study on 28 specimens of vitreous or subretinal fluid removed from patients with PVR. Five main types of cells could be identified: heavily pigmented cells, poorly pigmented ones, large totally unpigmented macrophage-like ones, smaller unpigmented cells and lymphocytes. Analysis of intravitreal pigment granules showed two different types of pigmented cells, those with lipofuscin and melanin and those with melanin without any granules of lipofuscin, which could originate from ciliary or iris pigment epithelia. Immunostaining procedures confirmed the epithelial non macrophagic lineage of the intravitreal and subretinal cells. Lymphocytes were only B cells. These results confirm the importance of proliferative process during the course of PVR and shows the involvement of other ocular structures other than the retinal pigment epithelium.