Transparent indium tin oxide microelectrodes were fabricated and used to immobilize suspended NIH 3T3 fibroblast cells by positive dielectrophoresis. The indium tin oxide electrodes facilitated microscopic observation of immobilized cells compared with opaque metallized electrodes. Dielectrophoresis was used to capture arrays of individual cells and form small cell clusters within a microfluidic network. The extent of cellular immobilization (no-cell, single-cell, or multiple-cell capture) was correlated with the applied voltage and inversely with the flow velocity. Specific conditions yielding predominantly single-cell capture were identified. The viability of immobilized cells was confirmed using fluorescence microscopy.