This work presents a fast, simple, and cost-effective technique for fabricating and integrating highly conductive 3D microelectrodes into microfluidic devices. The 3D electrodes are made of low cost, commercially available conductive adhesive and carbon powder. The device can be fabricated by a single-step soft lithography and controllable injections of a conductive composite into microchannels. Functioning of the microfluidic device with 3D electrodes was demonstrated through DEP particle switching as an example for a wide range of microfluidic applications.