Conjunctival epithelial cell growth and differentiation were studied by cultivating cells on tissue culture plastic surface and on natural substrata such as collagen gel and matrigel R . Well-differentiated goblet cells were unable to attach in plastic cultures and could only be preserved in collagen gel- or matrigel R - based cultures. Percoll density fractionation experiment suggested that, in the primary conjunctival epithelial cells, there were precursor cells for goblet and non-goblet epithelial cells. The goblet cell phenotypic expression of these precursor cells was influenced by the surface to which they attach and by the serum factors. The PAS and AM-1 positive cells could also be induced when the precursor cells are cultured on collagen gels in serum-free define medium supplemented with retinoic acid. To study how the goblet cell precursors are differentiated and from what stem cells they are derived, it is necessary to develop a culture system with a better mimicry of the in vivo conjunctival tissue. In this regard, we developed an in vitro conjunctival equivalent , in which the epithelial cells were cultured on fibroblast-contracted collagen lattice to allow continued cross-interactions of the epithelial and mesenchymal cells. This experimental model should allow experimental inquiries that are difficult, if not impossible, in conventional cell cultures.