This research. intitled the effect of organizational Structure in fulfilling the Library targets, aims at specifying the type of organizational structure and measuring the degree of the fulfilled targets in the academic central libraries at the north of Iraq: Mosul university central library, Duhouk university central library, Salahaldeen university central library in a duration between 1/7/2003 to 30/6/2004. The survey is used as a tool to collect information displayed to general librarians managers of libraries, chiefs of technical departments and units and administration managers. The main results of this research reveal the followings: The organizational structure of Mosul central library is mixture between mechanism and organism structure while the other two libraries is that of a mechanic structure. The percentage weight in order to attain library targets reaches to (78.6) at Mosul central library, while it reaches to (52.2) at Duhouks and reaches to (49.2) at Salahaldeen.