Résumé : Introduction: assessing the knowledge, attitudes, practices and behaviors among blood donors in South Kivu and identify risk factors for viral markers. Methods: a descriptive and analytical cross-sectional study involved 595 blood donors in the city of Bukavu (Head city of the province of South Kivu) in the eastern Democratic Republic of Congo. Results: our sample consisted of 70.3% men with a median age of 23 and 77% of young people fewer than 30 years. The score of knowledge and attitude of blood donor's volunteer on blood safety were assessed at 23.5% and 79.1%. A statistically significant difference was observed between the loyal and new blood donors volunteer (25.1% vs 64.6% p < 0.001); between blood donors volunteer of low and high education level (p = 0.04). Motivation to donate blood in 95.9% of cases respect ethical rules of donation. The prevalence of viral markers in blood donors is as follows: 4.8% hepatitis B, 3.9% hepatitis C, 1.6% HIV. For HIV, the low level of education and replacement blood donors are most at risk, the antigen of hepatitis B is observed in blood donors over 30 years, blood donors living couple. Conclusion: general knowledge on blood safety is very low in the first link in the chain transfusion (blood donors). A good education of this population conducted by the transfusion service reinforced building (training and support) is needed.