OBJECTIVES: Several biosimilar products have been developed and marketed in Japan. However, the degree of understanding of biosimilars among healthcare professionals is uncertain. The objective of this study was to investigate the extent of awareness and understanding of biosimilars among Japanese physicians and pharmacists. METHODS: This was a non-interventional, web-based survey conducted in May 2015. Japanese physicians (rheumatologists/oncologists) and pharmacists voluntarily participated and provided their thoughts via questionnaires. Rheumatologists who have seen >= 30 rheumatoid arthritis patients/month on average and have prescribed biologics (Remicade/Humira, etc.) to at least one patient, and oncologists who have seen >= 30 cancer patients/year with use of biologics (Rituxan/Avastin/Herceptin, etc.) to at least one patient were eligible. RESULTS: Of screened physicians, about 35% have never heard of "biosimilar", whereas 96% of pharmacists were aware of "biosimilar". One hundred rheumatologists, 120 oncologists (30 each for Hematology/Breast/Gastroenterology/Respiratory) and 90 pharmacists who met the criteria and were aware of biosimilar were analyzed for a further questionnaire. 73% of rheumatologists and 82% of oncologists recognized that biosimilars "are relatively less expensive" and 62% of physicians simply answered "subsequent product/generic". 58% of rheumatologists showed an intention to prescribe future biosimilars, whereas 73% of oncologists showed prescription intention. The main reason behind this was "reduction of burden on patients", followed by "confirmed similarity in efficacy/safety". Physicians with little intention to prescribe biosimilars showed strong concerns for similarity to the innovator (>70%) and insufficient clinical data in efficacy/safety perspectives. Similarities in clinical efficacy/safety were more emphasized compared to structural and functional similarities in biosimilar development pathways. CONCLUSIONS: Awareness of biosimilars amongst Japanese physicians was still low with a strong leaning toward burden on patients and sufficient clinical data to confirm the similarity. Providing learning opportunities for general tenets of biosimilarity and its development pathways are vital to increase public recognition of biosimilars.