Abstract: Background: The coronavirus (COVID-19) pandemic has led to rapid changes in our society and healthcare system. Cancer patients and survivors may be disproportionately affected by these changes, including decreased access to healthcare, increased infection risk, and economic challenges. We sought to determine the effects of the pandemic on thyroid cancer survivors’ quality of life. Methods: An anonymous web-based survey was administered in collaboration with ThyCa: Thyroid Cancer Survivors’ Association, consisting of questions about (1) demographics, (2) thyroid cancer clinical characteristics, (3) attitudes toward and impact of COVID-19, and (4) the Patient-Reported Outcomes Measurement Information System (PROMIS) 29-item profile. The survey was linked on the ThyCa homepage. PROMIS measures were scored using item response theory models with a T-score metric relative to U.S. reference data via the HealthMeasures Scoring Service (https://www.healthmeasures.net). T-scores were analyzed using Mann-Whitney U, Wilcoxon signed-rank, Kruskal-Wallis, and Spearman’s rank correlation tests. Results: From 5/6/2020 - 10/8/2020, 505 participants accessed the survey, and all completed surveys by U.S.-based thyroid cancer survivors were analyzed (n=378, 75%). Mean age was 53 years, 89% were female, 90% were white, 74% had papillary thyroid cancer, 97% had surgery, and 70% received radioactive iodine. The vast majority agreed or strongly agreed (83%) that their lives were very different during COVID-19, as was the way they interacted with their doctors (79%). Less than half (43%) agreed or strongly agreed that they were satisfied with the amount of information from their doctor’s office regarding COVID-19 changes. Compared to previously-published PROMIS data for this population, T-scores were significantly higher in the domain of anxiety/fear (57.8 vs. 56.5, p<0.01) and lower for ability to participate in social roles and activities (46.2 vs. 48.1, p<0.01). Younger age was weakly correlated with greater anxiety/fear (Spearman’s rho=-0.38, p<0.01), and greater anxiety/fear was associated with pending treatment (p<0.01), lower cancer stage (p=0.01), and female sex (p=0.02). Conclusions: During the COVID-19 pandemic, thyroid cancer survivors reported increased anxiety/fear and decreased social participation. In our efforts to care for patients both physically and mentally as the pandemic continues, we must better understand their fears and concerns and improve communication about potential changes to their care.