Background. The aim of study was estimation of DVT risk factors after total hip or knee replacement and revisions after THA or TKA. Material and methods. There were reviewed series of 80 patients who had performed total hip or knee replacement or revisions after THR. All patients qualified to study were taken medical history and physical examination before operation. Time of surgery, kind of anaesthesia, volume of fluids transfused and blood loss, time of tourniquet use in TKR were noted during operation Volume of fluids transfused, blood loss, time of patients mobilizing were noted after operation. In postoperative period precise lower limbs examination was performed every day. Laboratory tests (among others D-dimers level in serum) and two-dimensional ultrasonography, completed by Doppler were repeated several times. In all cases the same kind of pharmacological prophylaxis was administered. Results. There were analyzed several factors influence DVT: patient sex, age, BMI, concomitant diseases, past surgical procedures, smoking, kind of anaesthesia, time of surgery, blood loss during and after operation, volume of fluids transfused, time of patients mobilizing after surgery, time of tourniquet use in TKR. Conclusions. The risk factors of DVT after joints replacement are: age over 60 years, obesity, concomitant limbs varices, past deep vein thrombosis, concomitant cardiac arrhythmia, long lasting operation, serious blood loss after surgery, delayed patients mobilizing after operation.