The aim of this study was to investigate the effect of chronic treatment with chromium hexavalent (Cr VI) on the platelet activation, inflammation and lipid peroxidation in rats. Thirty male Wistar rats weighing 251 ± 18 g were randomly assigned to one control and one Cr-exposed group. 8-iso-prostaglandin F(2α) (8-iso-PGF(2α)), interleukin 1β (IL-1β), tumor necrosis factor alpha (TNF-alpha) and creatinine (Crt), were measured in plasma, while 11-dehydro thromboxane B₂ (11-dehydro-TXB₂) in plasma andurine. Plasma levels of IL-1β, TNF-alpha, 8-iso-PGF(2α) and Crt were significantly increased in the Cr (VI)-treated in comparison to the control group. Also, in the urine of Cr (VI)-treated rats, 11-dehydro-TXB₂ was significantly increased in comparison to control rats. From the obtained data it is evident that chronic treatment with Cr (VI), accelerates arachidonic acid peroxidation in rats, which peroxidation further probably induces enhanced 11-dehydro-TXB₂ excretion rate.