Background and Objective: There is a challenge in recruiting and retaining of the potential blood donors for repeat blood donation especially in developing countries including Tanzania. The aim of this study was to determine factors associated with repeat blood donation. Methods: This was cross sectional study carried out among blood donors aged 18-65 years in Northern, Tanzania. The questionnaire was administered among 454 participants through the phone. Data was entered and analyzed using Statistical Package for Social Science (SPSS). Results: Of the 454, the proportion of repeat donation was 63.9%. Sex, living place, high intentions to donate, knowledge on blood transfusion interval, good previous experience, altruistic behaviors score were significantly associated with repeat donations. In the backward logistic regression analysis, the significant predictors were living in Arusha which had lower odds of repeat donation by 0.466 times (P=0.002) and those living outside Northern Zone had higher odds by 2.1 folds (P=0.049) to repeat donations compared to those living in Kilimanjaro. Knowledge on time interval between donations increased odds of repeating donations by 55.4 % (P=0.039) than who had incorrect knowledge. High intention increased odds of repeat donation by 2.1 folds (p=0.001) compared to low intention. Altruistic score had minor effect on increasing odds of repeating donations by 2.5 % (p=0.036). Conclusion: Repeat blood donation is affected by proximity of donating site, awareness on the blood donation interval, intention to donate and experience on previous donation. We recommend continuous education concerning blood donors and donation is highly among health workers and society as whole, this will create awareness on motivational factors for repeat donations. Key words: Repeat donation, Blood donor, Tanzania, intention