The origin of the Postgraduate School at UNAAB is traceable to the setting up of a Postgraduate Committee in February 1992.  The postgraduate Committee, under the Chairmanship of the then Deputy Vice-Chancellor, Professor G. M. Babatunde, undertook the preparation of guidelines and modalities for the establishment of a Postgraduate school and the commencement of postgraduate programmes.  Based on the Committee's report, Senate approved the establishment of the Postgraduate School on 16 December 1992.  The first sets of postgraduate students were admitted during the 1992/93 and 1993/94 academic sessions.  Professor B.K. Ogunmodede was the foundation Dean of the Postgraduate School (1993-1995).  The Postgraduate regulations underwent extensive revision to reflect new developments and programmes by the Postgraduate School Board, which were approved by Senate during 1998/99 academic session. Professor O. A. Osinowo who succeded Professor Ogunmodede published the first edition of Postgraduate Prospectus reflecting these revised regulations.

Postgraduate education at UNAAB aims at imparting specialized knowledge and skills leading to the attainment by the student of a high level of expertise in a specific field of agriculture, forestry, engineering or the basic sciences. These objectives are met through the institution of an appropriate mix of advanced courses, provision of excellent research and library facilities, as well as teaching and supervision by highly experienced postgraduate academic staff.  In general, considerable effort is being made on a continuous basis by the University to provide a conducive environment for postgraduate study.