Gaining physician confidence is critical to securing a meaningful position in developed markets; therefore, understanding their concerns about biosimilar products should be an important part of development and marketing strategies. We conducted primary market research with specialist physicians across the United States and Europe to understand their perspectives on biosimilars and their expectations for use. To understand how physician attitudes vary across therapeutic fields, we surveyed six different types of specialists and posed questions about key topics that will influence uptake. We uncovered the trends in physician perceptions about biosimilars over time and how physicians from different specialties and geographies vary with respect to their opinions on automatic substitution, indication extrapolation, drivers and barriers of uptake, clinical concerns and requirements, and competition from new innovative biologics. This report is part of Decision Resources Group’s Biosimilars Advisory Service, which provides in-depth market analysis supported by our primary market research with physicians and payers and delivered through regular webinars that put major events into context. Interactive forecasts allow assessment of market opportunities and strategically focused reports help shape biosimilars development and defense strategies.