OBJECTIVE: To define the importance of leukocyte recruitment in endotoxin-induced gut permeability. MATERIALS AND METHODS: 31 male C57BL/6 mice were challenged with lipopolysaccharide (LPS). Ileal permeability was measured in Ussing chambers and leukocyte-endothelium interactions studied with intravital fluorescence microscopy after 18 h. RESULTS: LPS caused a clear-cut increase in leukocyte accumulation and intestinal permeability. Immunoneutralisation of P-selectin not only reduced leukocyte recruitment significantly (54 % reduction) but also abolished endotoxin-induced intestinal leakage. Intestinal levels of pro-inflammatory chemokines increased markedly in response to LPS but were not influenced by inhibition of P-selectin in vivo. CONCLUSION: The present study shows not only that endotoxin-induced leukocyte recruitment is mediated by P-selectin but also that sepsis-associated intestinal leakage in the gut is largely regulated by leukocyte accumulation. Thus, our novel data demonstrate a critical link between P-selectin-dependent leukocyte recruitment and gut barrier failure in endotoxemia.