This article presents the test results of injection processes of diesel-bioethanol fuel blends on a high pressure common rail injection system. The injection characteristics were analyzed using the injection rate measuring instrumentation. The injection rate, cycle injection quantity, injection delay and injection duration were analyzed across a range of injection pressure and injection energizing time. As the results show, the peak injection rate and delay of diesel-ethanol blends are lower compared to diesel fuel. The injection duration and discharge coefficients of diesel-ethanol blends were lower than those of diesel fuel. It was observed that fuel density and fuel viscosity have significant influence on the injection characteristics.