OBJECTIVES: To evaluate venous thromboembolism (VTE) rate and incremental costs during hospitalization for total knee (TKA) and hip arthroplasty (THA) in public and private health system. METHODS: Retrospective cohort study of patients undergoing elective TKA or THA in 2010.  All reviewed charts were from either one public or two private hospitals in São Paulo state, Brazil. Patients were 18+ years old, and excluded from the study if antithrombotic drugs were used prior to surgery. Costs were estimated based on hospitalization resource utilization described in patients´ chart. Costs are expressed in 2012 US$. RESULTS: From a total of 233 patients, 215 were included: 121 (56.3%) TKA and 94 (43.7%) THA. A total of 203 (94.4%) patients received VTE prophylaxis, being enoxaparin the first choice in 201 (99%). VTE was suspected in 7 (3.3%) cases during hospitalization (4 TKA/3 THA). VTE was confirmed in two cases from private hospitals: one deep vein thrombosis (DVT) and one DVT/pulmonary embolism, both TKA. In the public setting (N=81), length of stay (LOS) and hospitalization average cost per patient were 4.9 (SD3.8) days and US$2,327.12, respectively, in non-VTE group (N=79) while 13 (SD9.0) days and US$3,121.01 in suspected VTE group (N=2). In the private setting (N=134), LOS and hospitalization average cost per patient were 5.1 (SD3.0) days and US$14,006.28, respectively, in non-VTE group (N=129), 15.7 (SD11.3) days and US$22,006.33 in suspected VTE group (N=3), and 22 (SD7.1) days and US$28,232.33 in confirmed VTE group (N=2). CONCLUSIONS: In our study, VTE rate was 0.9%, increasing four times the LOS  and doubling hospitalization costs (US$ 14,226.05/patient) for the private service when comparing to patients without event. LOS of suspected patients was similarly extended in both health services yet with higher hospitalization cost for the private setting.