The serological screening of blood donors has been instituted by the Brazilian Ministry of Health and is mandatory in the research on several diseases transmissible through blood transfusion. Blood banks need to establish a screening service capable of reducing associated transfusions risks.The objective of this study was to establish the prevalence of transfusion-transmissible infection markers in donors at a hemotherapy service located in southwest Bahia, Brazil.A retrospective study was performed between 2010 and 2016. Variables, such as the characterization of donors who were suitable and unsuitable for donation (in clinical screening), stratification by gender and age group and unsuitable samples for reactive test results (in serological screening) by aspecific antibodies against hepatitis B virus (anti-HBc and HBsAg), hepatitis C virus (anti-HCV), human T-lymphotropic virus (anti-HTLV I/II), HIV virus (anti-HIV I/II), chagas disease, and syphilis markers, were evaluated.Collected data showed that 3.13% of the donors were considered unsuitable for serological screening and that the prevalence of reactive test results was higher in donors aged between 30 and 39 years and in males. The means of the serological markers was 1.09% for syphilis reagents, 0.63% for anti-HIV I/II, 0.51% for anti-HBc and anti-HCV, 0.15% for HBsAg, 0.14% for HTLV I/II and 0.10% for Chagas disease.These results reflect the importance of awareness campaigns on sexually transmitted diseases and transfusion safety measures taken by hemotherapy services.