Objective: To identify the organizational structure and medical contributions of Medical Affairs/Medical Science Liaison (MA/MSL) and its impact on the spread of the coronavirus-19 (COVID-19) infection.Method: We conducted a web-based survey for 45 pharmaceutical companies based in Japan. The outcome of 43 questions related to organizational structure, business activities, key performance indicators (KPI), and indicators of medical contribution were analyzed and compared.Results: Responses were received from 43 pharmaceutical companies (95.6%; 26 Japanese and 17 foreign). The total number of MSLs exceeded 1,000 with an average of 30.1 MSLs/company. MSLs supervised an average of 21.8/MSL Key Opinion Leaders/Key Thought Leaders (KOLs/KTLs). There were eight MSL organizations per company on average, and Phase II/III had the most number of MSL organizations. Further, 22 companies (56.4%) had MSL organizations in the oncology area. All the companies were independent from departments mainly engaged in "sales and promotion activities," and the most common KPI was “collection insight from KOL/KTL.” Despite having medical qualifications and highly specialized degrees, training was provided continuously to improve expertise. Based on the life cycle of products, Japanese companies are promoting evidence generation and medical events with KOL/KTL supported by internal and external insights and foreign companies are promoting medical-education activities. Due to the COVID-19 pandemic, the number of “in person” activities have significantly decreased and that of "online" activities have increased considerably, and this trend might continue even after the end of the pandemic.Conclusion: The organizational structure and medical contribution of MA/MSL are partially different between Japanese and foreign companies. MSL continued to increase; however, the organization and activities were affected by the product.