Background: ASCO recommends that patient-physician treatment discussions include addressing costs of cancer care; when and how these conversations should optimally take place is unclear. We sought to determine contemporary attitudes of US cancer physicians toward discussing treatment costs as a part of medical decision-making. Methods: A 15-question, self-administered, anonymous, electronic survey was distributed to US ASCO physician members after conducting 10 pilot interviews to improve usability and face validity. Differences in answers among groups were compared using simple logistic regression with 2-sided p-values. Results: 333 of 2290 physicians responded (RR=15%; 35% medical oncologists, 35% radiation oncologists, and 31% surgeons; 45% academic, 55% community practice). Overall, 67% agreed that doctors should discuss costs of care with patients; 33% disagreed. 60% reported addressing costs frequently/always and 40% rarely/never in their own practice. Medical oncologists were more likely than radiation or surgical oncologists to discuss costs with patients (OR 3.14 and 3.75, p≤.00001). Compared to community physicians, academic physicians were less likely to discuss costs (OR 0.41, p=.00012), and felt less prepared for such discussions (OR 0.492, p=.005), but were more likely to consider costs to the patient (OR 2.68, p=.02) and to society (OR 1.822, p=.02) when planning treatment. Physicians who reported frequent discussions were significantly more likely to prioritize treatments in terms of cost, have a sense of their patients’ financial well-being, feel their patients were well-informed about costs and believe doctors should explain both out of pocket and societal costs of care to their patients. Surgeons were most likely to refer patients to financial counselors (p=.01). The most common reported barriers were lack of resources to guide cost discussions (58%) and lack of time (44%). Conclusions: Though a majority of oncology physicians believe it is important to discuss costs of care, practice is inconsistent and there is no consensus on when and how to discuss costs. There is a need to define the goals and content of cost discussions and to address perceived barriers that limit this aspect of quality cancer care.