Integrated on-chip whole blood sample pretreatment includes blood cell separation, cell lysis and DNA extraction. Compared to macro-counterparts, whole blood sample pretreatment using integrated microfluidic devices has the advantages of low sample consumption, short time-scale measurement and high portability. In this chapter, reported integrated microfluidic devices for blood sample preparation are briefly summarized and compared. And then a specific microfluidic chip with the function of cell separation, cell lysis and DNA extraction is proposed for detailed discussion. The integrated microfluidic device is capable of pre-treating whole blood samples, paving ways for the eventual integration of sample preparation, PCR, and electrophoresis on a single chip in the field of point-of-care genetic analysis, environmental testing, and biological warfare agent detection.