Preventable venous thromboembolism (VTE) and "appropriate" type, dose, and duration of prophylaxis are emerging concepts. Contemporary definitions by key quality organisations, including the World Health Organization, have shifted towards "preventable" VTE being considered an adverse event or adverse drug event. A decision tree and cost model were developed to estimate the United States health care costs for total deep-vein thrombosis (DVT), total hospital-acquired DVT, and total "preventable" DVT. Annual cost ranges were obtained in 2010 US dollars for total ($7.5 to $39.5 billion), hospital-acquired ($5 to $26.5 billion), and preventable ($2.5 to $19.5 billion) DVT costs. When the sensitivity analysis was applied--taking into consideration higher incidence rates and costs - annual US total, hospital-acquired, and "preventable" DVT costs ranged from $9.8 to $52 billion, $6.8 to $36 billion, and $3.4 to $27 billion, respectively.