Introduction: repetitive altruistic donors are relevant to blood banks because of the evidence of low risk for transfusion transmitted infections. However, studies about clinical and hematological characteristics are exiguous in our country. Objective: to describe the clinical and hematologic characteristics of repetitive blood donors in a blood bank of Medellin-Colombia. Materials and methods: descriptive study of a retrospective cohort. The information was collected from the blood bank database. The measures of summary and frequency were calculated. The clinical and hematological characteristics were compared according to sex and age; in addition, the relation among hemoglobin values and time between donations was evaluated. Results: the cohort consisted of 556 donors; the annual average of donation was two. The clinical characteristics differed by sex and age. Between donations, there were statistically significant differences with the body weight, which increased and the media blood pressure and the hemoglobin, which decreased. Conclusions: the clinical characteristics showed changes between donations without exceeding the established limits. This implies it is important the steady care of each clinical and hematological parameter evaluated, in order to preserve donor health and guarantee their revisit, with special attention to female donors.