BACKGROUND: Ulcerative colitis (UC) is a chronic and debilitating inflammatory bowel disease. While there is no cure, patients and physicians can choose from a variety of treatments characterized by different attributes such as efficacy, safety, and mode and frequency of administration. Hence, it is important to understand how (and to what degree) these attributes influence treatment preferences from both patient and prescriber perspectives. Therefore, the purpose of this study was to elicit patient and physician preferences for different attributes of UC treatments via a discrete choice experiment (DCE). METHODS: The study was conducted in the United States (US) in 2 phases: (1) a qualitative phase involving in-depth individual interviews with patients and physicians to explore the UC treatment attributes that patients and physicians consider most important when making treatment decisions, and (2) a quantitative phase to estimate the relative importance of those attributes. Screening criteria for patients (self-reported clinical diagnosis of UC, disease severity of moderate to severe based on self-reported medication history) and physicians (gastroenterologists with experience treating patients with moderate to severe UC) were consistent across phases. In the quantitative phase, 2 discrete choice experiment survey instruments (one for patients, one for physicians) with an identical set of UC treatment attributes were developed and administered. The resulting data were analyzed using a random-parameters logit model to estimate preference weights and conditional relative importance of UC treatment attributes. RESULTS: Two hundred patients with moderate to severe UC and 200 board-certified (or eligible) gastroenterologists completed the survey. The average age of patients was approximately 42 years, and the majority of patients (59%) were female. In the qualitative phase, both patients and physicians indicated that the most important UC treatment attributes were time to symptom improvement, chance of long-term symptom control, risk of serious infection, risk of malignancy, mode and frequency of administration, and need for use of steroids. For patients, symptom control was 2.5 times more important than the time to symptom improvement. Patients considered a 5-year risk of malignancy almost as important as long-term symptom control (relative importance of 0.79 compared with 0.96 for long-term symptom control) and preferred all suggested pill-dosing schedules to both subcutaneous injections and intravenous infusions (relative importance of 0.47 compared with 0.11 and 0.18, respectively). For physicians, symptom control was by far the most important attribute when prescribing a treatment, and it was 5 times as important as the 5-year risk of malignancy. CONCLUSION(S): We identified patient and physician preferences for UC treatments. The differences in results between patients and physicians suggest that patients are thinking about the treatment features differently from their physicians. Both patients and physicians identified long-term symptom control as the most important attribute relative to the others; however, the 5-year risk of malignancy was almost of equal importance to patients but not for physicians. This highlights the need for improved communication about the relevant benefits and risks of different UC treatments so that patients and physicians can engage in better decision making.