Human carcinomas of the pancreas are aggressive tumors which traverse basement membrane barriers during invasion and metastasis. In order to examine the relationship of pancreatic tumor cells to basement membranes, we analyzed and compared the capabilities of four biologically different human pancreatic adenocarcinoma lines to adhere to substrate coated with purified basement membrane constituents. Each of the four cell lines adhered readily to purified laminin in a dose-dependent manner, although differences were noted in the time required for optimum attachment. Significant variations in the abilities of the cell lines to attach to purified fibronectin were evident both in concentration dependence and in the time required for attachment and spreading. Adhesion to type IV collagen was negligible for two of the four tumor lines but addition of soluble laminin or fibronectin augmented attachment. The other two cell lines attached only moderately to type IV collagen and this attachment was not enhanced by soluble laminin or fibronectin. When laminin or fibronectin was coated directly over type IV collagen, attachment of all four cell lines was comparable to that for the glycoproteins alone. Although the tumor lines were all established from human neoplasms of similar histological origin and retained the ability to adhere to intact basement membranes prepared from human amnion, they exhibited various patterns of attachment to laminin, fibronectin, and type IV collagen.