This study aimed at looking into the demand and utilization of blood and blood components at a tertiary teaching hospital in Ethiopia. Methods: A cross-sectional study was conducted from June 1, 2018 to August 31, 2018 at St Paul's Hospital Millennium Medical College. Data on the types of blood products requested, indication for transfusion, availability of blood products and the utilization of different blood components, were collected by a structured questionnaire. Data were entered into SPSS version 20.1 and presented as frequency and percentage. Results: Blood and blood components were requested for 819 patients during the study period. Blood group O RhD positive was the commonest blood group (BG) accounting for 292 (35.7%) of the study participants followed by blood group A RhD positive 259 (31.7%). Physicians requested 3290 units of blood and blood components for transfusion; however, only 1840 (55.9%) were available and transfused. Of the 1840 transfused blood and blood components, 771 (42%) were packed RBC, 460 (25%) platelet, 352 (19%) fresh frozen plasma, and 257 (14%) whole blood. Postpartum hemorrhage was the commonest indication of blood transfusion in obstetrics, while severe anemia was the leading emergency situation in pediatrics and internal medicine departments. Abdominal trauma was the leading indication of blood transfusion in the department of surgery. Conclusion:This study finds a serious shortage of blood during emergency hours that may have a significant impact on patient survival. The hospital, in collaboration with the national blood bank, should devise a mechanism to alleviate the shortage.