Background: A clear understanding of patients' preferred treatment outcomes is necessary to guide treatment decision-making. In this study, we sought to quantify the treatment outcome priorities of older adults (≥ 60 years old) newly diagnosed with hematologic malignancies and to describe individual patient's willingness to tolerate specific treatment-related benefit-risk tradeoffs. Methods: We developed a values elicitation measure using best-worst (BW) scaling and direct elicitation through a community-centered approach engaging diverse stakeholders. The measure includes 7 treatment priorities: Living longer, Maintaining day-to-day activities, Avoiding becoming more dependent on others, Avoiding hospitalizations/Increasing time at home, Avoiding long-term side effects, Avoiding short-term side effects, and Avoiding high financial costs. Patients complete repeated choice tasks choosing the most and least important treatment priority among repeated subsets using a balanced-incomplete block design. Direct elicitation was used to determine specific benefit-risk tradeoff preferences. Recruitment occurred at a public safety-net hospital following pathologic diagnosis. Patients completed the measure prior to the initial treatment decision and longitudinally each month. Data from the BW scaling measure were analyzed using the count method (best minus worst) and standardized. Results: In total, 48 patients consented (48% lymphoma, 40% leukemia/myelodysplastic syndrome, 12% other). Mean age was 74 years (range 60 - 95); 59% were male; 96% were white; 67% had a bachelor's degree or higher. Fifty-two percent (n=25) fully completed the BWS instrument at least once. The ranked importance of priorities for the entire cohort was 1) Maintaining day-to-day activities (standardized best minus worst, 23.8), 2) Living longer (12.4), 3) Avoiding becoming more dependent on others (7.9), 4) Avoiding hospitalizations/Increasing time at home (2.2), 5) Avoiding long-term side effects (-5.2), 6) Avoiding short-term side effects (-19.5), and 7) Avoiding high financial costs (-21.5). The most important outcomes (including ties) for individual patients were Maintaining day-to-day activities (40% of patients), Living longer (40%), and Avoiding becoming dependent on others (20%), while the least important outcomes were Avoiding high financial costs (52%), Avoiding short term side-effects (32%), and Living longer (20%). Thirteen (52%) patients completed subsequent BWS surveys; 69% changed their most important outcome at least once. Direct elicitation demonstrated that patients were willing to accept additional hospital stays of 1 week (88%), 1 month (58%), and 3 months (25%) in exchange for an additional 6 months of life. Only 25% of patients indicated willingness to require a full-time caregiver in exchange for an additional 2 years of life, whereas patients were more willing to accept a part-time caregiver in exchange for an additional 1 month (38%) or 6 months (79%) of life. Some patients were unwilling to accept an additional 6 months of life if it meant requiring assistance dressing (33%) or bathing (54%). In exchange for an additional 6 months of life, patients were willing to spend $250 (83%), $500 (58%), or $1000 (42%) per month. Conclusions: Older adults with newly diagnosed blood cancers differed when prioritizing treatment outcomes. Maintaining function was highly valued and was frequently more important than prolonging survival. Some patients felt prolonging survival was least important. Many patients changed their treatment priorities over time. These results highlight the need to elicit treatment outcome priorities at the time of each significant treatment decision for older adults. Further, they suggest that endpoints other than overall survival should be considered for clinical trials in this population as prolonging survival may not be prioritized by most patients. This study also demonstrated that a combination of BW scaling and direct elicitation was able to quantify patients' treatment outcome priorities and benefit-risk tradeoff preferences, highlighting the potential for the development of similar values elicitation measures to be used to inform specific treatment decisions in various clinical contexts.