This work presents label-free separation of cells in an on-chip flow cytometer based on impedance spectroscopy. The amplitude, opacity, and phase information can be used for discrimination depending on the cell types. Red blood cells, ghosts, and fixed cells are differentiated based on differences in their membrane and cytoplasm dielectric properties. Among other applications, detecting changes in cell conductivity and membrane capacitance will allow the indentification of early-stage apoptosis or cancer.