In animal studies, many authors have observed coagulation activation in decompression illness (DCI). These hemostasis modifications have been attributed to circulating bubbles. We have studied molecular hemostasis markers in 25 consecutive divers, victims of DCI admitted to our hyperbaric center, and in 15 control divers. There was no significant difference in parameters studied in the patients and the control group (platelet, fibrinogen, antithrombin III, Thrombin Antithrombin III complexes, and D-Dimers). An activation of coagulation (D-Dimer > 500 ng.ml-1) was noted in three divers with neurologic troubles. However, such signs of coagulation activation were not correlated with the risk of sequeals. No control or study patient with an osteoarticular or vestibular accident presented signs of coagulation activation. Thus, there does not seem to be a correlation between the severity of the accident and the level of coagulation activation. Further studies will be necessary to evaluate the responsibility of hemostasis modifications in the physiopathology of decompression accidents in sports divers.