Background: Financial toxicity is increasingly recognized for its potential to adversely impact the quality of life and health outcomes of patients undergoing treatment for cancer. Patients with multiple myeloma (MM) may be particularly vulnerable due to high utilization of novel therapeutics and extended treatment duration. Methods: Patients with at least 3 months of ongoing treatment for MM were invited to participate in a survey during follow up visits at our institution. The survey was derived from published instruments and included the recently developed 11-item COST measure (financial toxicity score 0 – 44). Electronic health records informed insurance and treatment data. Results: Of 111 patients approached for the study, 100 individuals completed the survey. The median reported annual household income was between $60,000-79,999 and all participants were insured (43% private, 49% Medicare, 8% Medicaid/dual). Median time from diagnosis was 31 months, 75% had exposure to both lenalidomide and bortezomib, and 58% had undergone autologous transplantation. The majority (59%) labelled treatment costs as higher than expected and 70% endorsed at least minor financial burden. Thirty-six patients reported applying for financial assistance, including 18% of individuals with income over $100,000. Use of savings to pay for MM treatment was common (46%), 21% borrowed money to pay for medications, and 17% reported delays in their MM treatment due to cost. COST scores were normally distributed (median 20.5, range 0-43) and correlated with patient reported incomes, use of savings, borrowing of money, and treatment delays (p < 0.001). After controlling for potential confounders on linear regression, time since diagnosis was directly related (p < 0.03), while age and income were inversely related with COST scores (p < 0.03; p < 0.001). Conclusions: Financial burden and request for financial assistance were common in our insured population with MM. Younger age, lower household income, and time since diagnosis were associated with higher financial toxicity as measured by the COST score. Additional attention to rising treatment costs and cost-sharing is needed to address the growing evidence of financial toxicity impacting patients with cancer.