Proteomics is emerging as an important tool in modern drug discoveries and medical diagnostics. One of the techniques used in proteomics studies is 2-DE. The process of the conventional 2-DE is time-consuming and it has substandard reproducibility. Many efforts have been made to address the limitations, with an aim for fast separation and high resolution. In this paper, we reviewed the work on achieving 2-DE in microfluidic devices, including individual dimension in one channel, two dimensions in two intersected channels, and 2-D separation in a large number of channels. We also discussed the need for integrating microvalves within 2-DE devices to prevent different separation media from contaminating with each other. Although more efforts are required to match the performance of conventional 2-DE in a slab gel, microfluidics-based 2-D separation has a potential to become an alternative in the future.