Laminin along with collagen type IV, proteoglycans, and entactin are major components of basement membranes. Basement membrane components are synthesized at high levels during development. The formation of specialized basement membranes may play important roles in cell and tissue function by influencing cell proliferation, phenotype, migration and gene expression as well as tissue architecture. The growing diversity of laminin isoforms influences the formation of distinct basement membranes. Many of the laminin chains sequenced to date are expressed during glomerular development under strict temporal control. Also, some studies suggest that additional laminin chains exist and contribute to unique isoforms expressed within the renal glomerulus. This article will review the status of characterization of laminin isoforms expressed by glomerular cells, point out possible differences in isoforms expressed by different species, and discuss the implications of the complexity of glomerular laminins. In order to fully understand the nature of the glomerular laminins and their importance, information from studies of cells in culture, whole tissue, and those that use molecular and protein analysis must be integrated.