The purpose of our investigations was to answer the question of whether an increased number of cytoskeletal structures (CSS) in endothelial cells (EC) of the mesenteric terminal vascular bed will be seen in the early phase of a traumatic haemorrhagic shock (THS). A THS was induced in 32 adult R-rats according to a standardized model (fracture of right heel and withdrawal of one third blood volume through carotid catheter). Eight animals each time were killed 15, 30, 60, and 120 minutes after shock induction. Tissue samples of mesenteric microvessels were taken and flatly embedded in Epon. The mesenterium of 8 animals was used as control. CSS formed in the perinuclear and/or peripheric regions of endothelial cytoplasm were visually evaluated and divided into 3 degrees on the basis of 1,500 micrographs. Results were statistically analyzed. A significantly higher degree of CSS (microfilaments, intermediate filaments and microtubules) in EC was found in all shock groups as compared with the control group. CSS are frequently clearly seen in oedematous and swollen EC as well as in EC rich in organelles. Capillaries with stasis are especially predisposed to CSS. Different factors as changed interaction between vascular content and EC, hypoxia and ischemia as well an increased metabolic activity of EC have to be considered as possible causes.