Originally limited primarily to researchers from medical and natural sciences, the Leopoldina  has increasingly embraced the empirical behavioral, cultural, social and human sciences since the early 1990s. It is the member strongest among German academies with more than a quarter of its members coming from other countries.

The Leopoldina elects approximately 50 new members each year in order to maintain its membership base. Researchers are admitted exclusively as full members and for life. The admission follows a nomination by Academy members and a multi-stage selection process by the Section, the Class, and the Presidium. Members actively participate in the Academy's work, for example by contributing to statements and recommendations, taking on reviewer activities, or participating in events.

Since its appointment as German National Academy, the Leopoldina has been committed to increasing the proportion of women among its members and is actively pursuing this continuous long-term process. As a result of additional elections over the past decade, the proportion of female scientists among its members has risen from 7 to 15 percent. Female scientists currently account for approximately one-third of all new members. This number exceeds the proportion of female scientists holding a professorship in Germany, which was approximately one-quarter in 2019.