This study aims to deane prototypes of professional librarians as well as their job requirements by analyzing international demands for librarianship. Demands analysis starts with examining librarian job posting websites in the US, UK and Canada, followed by inquiring incumbent librarians in Korea. As for the job requirements. the study parallels definitions by IFLA and ALA with job announcements by hiring institutions. As a result, we identified 21 professional librarian prototypes by subject(7), task(12) and object(2), and defined the job requirements as 1) MLS or equivalent school knowledge with undergraduate degree of library science, and/or at least six years of relevant business experience, or 2) at least nine-rear experience as a second-level full-time librarian with two-rear experience and/or professional training in the job relevant field.