This thesis reports design and implementation of a MEMS based spiral channel dielectrophoretic separator for cytometry applications. Main objective of the thesis is to separate leukemia cells from healthy leukocytes with respect to the differences in their dielectric properties. A novel MEMS based dielectrophoretic separator with spiral channels and concentric 3D electrodes has been proposed. The proposed geometry decreased the footprint, which reduces the device cost, without degrading the separation and quantization performances. Concentric electrode geometry enables continuous electric-field application with simple voltage supplies. Theoretical explanation of the design has been presented and supported with finite element method simulations. Evolution of the design has been explained in conjunction with solutions to arising problems, chronologically. Comparisons of the proposed system with respect to the existing systems in the literature have been given. The devices are fabricated using a 3-mask process utilizing suspended parylene channel process. The experiments are realized with 1 &mu / m and 10 &mu / m polystyrene beads. The results show that 1 &mu / m particles have an average speed of 4.57 &mu / m/s with 1.06 &mu / m/s standard deviation, and 10 &mu / m particles have an average speed of 544 &mu / m/s with 105 &mu / m/s standard deviation. The speed variation coefficient for 1 &mu / m and 10 &mu / m beads can be calculated as 23% and 19%, respectively. The size accuracy of the device is &plusmn / 10%, while the resolution is 20%, that is, particles with radii different from each other by 20% can be separated. It is worthy to note that the experimental results almost match the simulation results.