OBJECTIVE To identify the main indications for bone marrow examination in a University hospital setup and the most common diagnoses encountered. To also identify the extent of correlation, if any, between the preliminary diagnosis and the result of the final bone marrow diagnosis. METHODS The requests and reports of all bone marrow biopsies and aspirations carried out during a 12-year period from January 1988 through to December 1999, in King Fahd Hospital of the University, Al Khobar, Kingdom of Saudi Arabia were retrospectively reviewed. The information extracted included the main indications for performing this procedure, age groups involved, and the most common diagnoses encountered. A specially designed form was used for this purpose and the data was analyzed using the statistical package for social sciences. Randomly selected slides of the most common diagnoses were reviewed to concur with the diagnosis. RESULTS There was a total of 1813 bone marrow biopsies or aspirations, or both, performed. The main indications for bone marrow examination in a descending order of frequency were the following: The diagnosis and management of acute leukemia 403 (22.2%), staging for lymphoma 276 (15.2%), evaluation of pancytopenia 215 (11.9%), thrombocytopenia 173 (9.5%), investigation of anemia 151 (8.3%), fever (pyrexia of unknown origin) 130 (7.2%), lymphadenopathy 120 (6.6%), and hepatosplenomegaly 80 (4.4%). The most common diagnoses encountered were: acute lymphoblastic leukemia 242 (13.3%), immune thrombocytopenia 123 (6.8%), acute myeloblastic leukemia 80 (4.4%), hypersplenism 79 (4.4%), chronic granulocytic leukemia 73 (4.0%), megaloblastic anemia 66 (3.6%), bone marrow positive for lymphomatous infiltration 63 (3.5%), chronic lymphocytic leukemia 40 (2.2%), and multiple myeloma 32 (1.8%). CONCLUSIONS This study confirms that bone marrow examination is a very important investigation for establishing the diagnosis in many conditions, especially hematological neoplasms. The most common indication for this procedure in our hospital was to confirm and manage acute leukaemia and the most common diagnosis was acute lymphoblastic leukemia.