OBJECTIVES: Use of innovative medicines in oncology and immunology is relatively lower in China compared to developed countries. This study aims to explore the willingness-to-pay (WTP) for these two therapeutic areas by understanding decisions driving physicians’ prescribing behavior and patients’ payment in immune diseases (rheumatoid arthritis, ankylosing spondylitis, and psoriasis) and oncology (prostate cancer). METHODS: For immunology, primary market research was done by interviewing 160 physicians with biologic experience, 200 patients consisting of patients who have not received any biologic treatments before (bio-naïve), and patients with biologic experience (bio-experienced).  For oncology, 50 physicians and 40  patients were recruited. All physicians and patients were recruited from large hospitals (tier 3A) from Tier 1, 2 cities. Patients were recruited to represent a diverse set of affordability. RESULTS: The results show that patients rely on physicians for treatment recommendation.  For rheumatoid arthritis, ankylosing spondylitis, and psoriasis, the top four factors driving physician’s recommendation are drug cost, patients’ ability-to-pay, safety of treatment and efficacy of treatment. For Ulcerative Colitis (UC) and Crohn’s Disease (CD), the top four factors were safety, efficacy, patients’ affordability followed by drug cost. The difference in pattern for UC and CD is likely attributed to the more severe nature of these diseases. Other factors such as injection frequency and mode of administration ranked lower for all indicators. For oncology, the top factors driving physician prescription are efficacy (overall survival, progression-free survival) followed by safety and tolerability. Patient affordability and drug cost are ranked much lower.  Similarly, from patients interview results, efficacy was rated more important than cost as a factor driving willingness-to-pay. CONCLUSIONS: Observations from these two therapy areas show that cost and affordability are the top considerations when the diseases are less severe. For severe diseases and  life-threatening diseases, efficacy and safety of the drug are rated more than drug cost.