Background: CD34+ cells infused predicts myeloid and platelet engraftment at the time of autologous stem cell transplantation. An association between the number of CD34+ cells infused and erythroid engraftment has yet to be established. Study design and methods: Red blood cells transfused after autologous transplantation were compared with the number of CD34+ cells infused. Myeloid engraftment was assessed to confirm that normal engraftment kinetics occurred. Results: Logistic regression established that the logarithm of the number of CD34+ cells infused (p = 0.0498) and admission hemoglobin (Hb; p < 0.001) predicted the need for transfusion. In those patients who required transfusion, standard regression methods were not valid. A novel model demonstrated that the initial Hb (p < 0.001) and diagnosis (p = 0.047) were significant predictors of transfusion requirements in patients needing transfusion. However, the number of CD34+ cells infused did not predict transfusion requirements in this group (p = 0.226). As myeloid engraftment demonstrated kinetics that have been previously described, it can be inferred that erythroid engraftment was not atypical. Conclusion: The number of CD34+ cells infused predicted the need for transfusion, although it did not predict the number of RBCs transfused in those patients having transfusion during their admission for autologous stem cell transplant.