This study examines the molecular mechanisms that underlie the observed preferential interactions of memory vs naive T cells with activated vascular endothelium. Many more CD4+ CD45RO+ (memory) cells adhered to 6-h TNF-alpha-activated human umbilical vein endothelium under flow than CD4+CD45RA+ (naive) cells. Adhesion studies were performed using Chinese hamster ovary (CHO) cell monolayers expressing human E- or P-selectin (CHO-E and CHO-P, respectively) or with soluble vascular cell adhesion molecule-1 (VCAM-1)-coated glass surfaces. Under flow at 1.8 dynes/cm2, RO+ T cells rolled extensively at low velocity on both CHO-P and CHO-E monolayers and VCAM-1, whereas very few RA+ T cells interacted with these surfaces. VCAM-1-dependent rolling was blocked completely by anti-very late Ag-4 (VLA-4) Abs. Purified CD4+RA+ T cells could be converted to RO+ cells by mitogen stimulation and 7-day culture in vitro, and this correlated with the acquisition of the ability to roll on E- or P-selectin, but not on VCAM-1 under flow. In summary, these data indicate that CD45RO+ cells interact with E- and P-selectins and VCAM-1 much more effectively than do CD45RA+ cells under flow conditions, and these adhesion pathways may contribute, either individually or in combination, to the preferential recruitment of memory T cells to peripheral sites of inflammation.