Sickle cell disease (SCD) is an important public health issue in Bahia, Brazil. Erythrocyte transfusions may reduce morbidity of SCD, however, they are associated with numerous risks. Among other risk categories, alloimmunization to red cell antigens may result from transfusions. The aim of this study was to compare the clinical profile of transfused adult SCD patients with and without alloantibodies. The study included 108 patients (105 homozygous SS and three with hemoglobinopathy SC), followed in the Outpatient Unit of the Hematology and Hemotherapy Center of Bahia. A retrospective review of clinical records of adult SCD patients who received at least three red blood cell transfusions from 2004 to 2007 was performed. Transfusion units were phenotypically matched for ABH-D and C,c,E,e, and K antigens. Alloimmunization developed in 56 patients (53 SS and three SC). The most prevalent alloantibodies were anti-E, anti-K, and anti-C (39.3%, 21.4%, and 16.1%, respectively). Age, sex and positive antiglobulin test displayed statistically significant differences. Prevalence of clinical complications such as leg ulcers, stroke, and others did not show differences between groups. In conclusion, alloimmunization did not significantly modify the clinical outcomes of SCD patients from Bahia, Brazil.