The main objective of this study was to determine the relationship between occurrence of malaria infection with that of human blood group in Dar-es-Salaam Tanzania. The study was based on data collected randomly from the patients who were screened for malaria of all age groups for a period of three months at Mission Mikocheni Hospital. During this time period, a total of 430 blood samples were collected. From the study findings, it is clear that more than 50% of the patients tested were positive for malaria. Further analysis revealed that about 50% of malaria positive patients were type “O” blood group.