Background: Cancer-associated thrombosis (CAT) occurs in 20% of cancer patients and is currently their second leading cause of death. Several scoring systems (i.e., Khorana Risk Score, COMPASS-CAT, Vienna-CATS, etc) have been developed to allow clinicians to determine CAT risk and prescribe appropriate treatments. There is little data about how hematologists and oncologists use these risk assessment models in daily practice. We conducted a survey of hematologists and oncologists in different institutions about their usage and opinions of CAT scoring systems. Methods: We created a twelve-question survey querying hematologists and oncologists regarding their usage and perspectives on CAT and scoring systems. Survey participation was voluntary, non-incentivized, and anonymous. The survey was advertised on social media and email list groups from January to February 2023. Descriptive statistics were analyzed in R version 4.1.2. Results: Seventy hematologists/oncologists responded with 88.4% from the US and 11.6% international. The plurality of respondents (35.7%) identified as sub-specialty oncologists (e.g., GI oncology, thoracic oncology, etc), 18.6% identified as malignant hematologists, and 15.7% identified as non-malignant hematologists. Overall 71.4% of respondents worked in academic settings. The majority (57.1%) stated they do not use any CAT scoring system and 15.7% stated they do not have familiarity with any CAT scoring system. Zero respondents strongly agreed that they often use scoring systems. Of the CAT systems used, the Khorana score was by far the most common (80.0%). Respondents somewhat agreed (14.3), somewhat disagreed (10%), or were undecided (34.3%) that scoring systems make it easier to determine CAT risk in practice. The majority (54.3%) were also undecided that these systems’ predictions of CAT risk are accurate. There was general agreement in worry of bleeding in anticoagulating cancer patients prophylactically (strongly agree 12.9%, agree 32.9%, somewhat agree 22.9%). Respondents strongly agreed (34.3%) or agreed (40.0%) that decisions about anticoagulation are important part in cancer patients’ supportive care. Similarly, respondents strongly agreed (30.0%), agreed (38.6%), or somewhat agreed (22.9%) that counseling patients on CAT is important. Conclusions: To our knowledge, this is the first survey assessment of hematologists and oncologists regarding their opions on CAT and their usage patterns of scoring systems. Despite the widespread agreement that counseling regarding CAT is important and that decisions about anticoagulation are a vital part of a cancer patient's supportive care, most clinicians do not use CAT scoring systems in practice or are not familiar with them. Hematologists and oncologists worry about the risk of bleeding with anticoagulation and agree there is a need for new and improved CAT scoring systems.