Blood-borne disease is one of communicable disease through blood contamination.The aims of this study to determine risk factors for diseases transmitted from blood donors in Semarang District. The design study was a cross sectional with analytic approach. The subjects were blood donors (400 people) using an accidental sampling method. Statistical analyzed with fisher exact test and prevalence ratio with 95% significance level. Results showed the prevalence of hepatitis B and HIV was 1.5% (6 people) and 0.5% (2 people). Hepatitis C infection in this study was not found. From the statistical test showed that history of sexual behavior as a risk factor incidence of infectious disease through blood POR = 30.992; 95% CI (6.908 -139.041) with p = 0.001. Knowledge, types of injection drug use, sharing needles, blood transfusions, organ transplants, surgery, dialysis, dental examination, tattooing and piercing, and contact with the patient were not risk factors for the incidence of infectious diseases through blood in Semarang District. Indonesia Red Cross in Semarang District should conduct dissemination to the blood donors on the sidelines of the implementation of activities related blood donor infectious diseases transmitted by blood including agent, transmission, natural history, prevention and treatment.