Patients affected by inflammatory bowel disease (IBD) frequently suffer from thromboembolic events. Aims of this study were to investigate hemostatic system and the presence of antiphospholipid antibodies (aPL) in IBD patients. Forty-one patients affected by Crohn's disease (CD) and 19 by ulcerative colitis (UC) were studied, compared to 40 healthy control subjects. Platelet count (PLT), PT, aPTT, fibrinogen (Fib), prothrombin fragment F1+2, antithrombin (AT), protein C (PC), protein S (PS), factor XIII (FXIII), plasminogen (PLG), plasminogen activator inhibitor (PA1), spontaneous platelet aggregation in platelet-rich plasma (PRP-SPA) and in whole blood (WB-SPA), and antiphospholipid antibodies (aPL) were evaluated. PLT, Fib, F1+2 and WB-SPA were significantly increased in IBD patients (p at least <0.05) both in active and inactive phases; aPL positivity was more frequent (p<0.05) and FXIII was significantly decreased (p<0.05) in comparison to control subjects. The thrombophilic state of IBD patients is not related to the degree of activity of the disease or to previous thrombotic events; aPL express the immunological alterations connected with IBD and are not the main cause of thrombotic events.