Thirty patients of Retinoblastoma presenting in the Haematology Department of King Edward Medical College, Lahore were included in the study to find out the bone marrow involvement. The patients underwent bone marrow aspiration and peripheral blood examination was also done. The aspirates were screened for the presence of tumor cells. Of the patients studied 21(70%) were males while 9(30%) were females giving a male to female ratio of 2.8:1. Maximum number of patients were in the 2-3years age group. Twenty seven patients had unilateral Retinoblastomas while three patients had bilateral disease at presentation. The bone marrow of three patients showed presence of tumor cells.