Samples of iris tissue were removed from human eyes with and without pseudoexfoliation syndrome and maintained in vitro for several weeks. The samples were cultured on tissue culture plastic as well as on biological basement membranes. The morphology of the cultures was examined by phase contrast-, scanning electron-, and transmission electron microscopy. Out-growth of cells with similar shapes was observed from normal iris as well as from pathological tissue on both type of substrate. In sections the outgrowing cells formed multilayered structures. In these areas the individual cells were separated by spaces containing extracellular material. The PE positive specimens revealed typical PE aggregates both within the native tissue and between the outgrown cells. Production of viable cell cultures from human eyes with pseudoexfoliation may facilitate the search for morphological and biochemical abnormalities in this syndrome.