Polymer synthesis requires strict control of reaction conditions such as temperature, reaction time, and mixing of reagents. Microfluidic reaction systems enable efficient mixing and rapid heat exchange. Moreover, laminar stream in a microfluidic channel enables control of the resulting shape of a molecule. This article reviews the use of microfluidic technology in the field of polymer chemistry. First, conformational aspects of polymers in microfluid are summarized. Next, the techniques for linear and branched polymer synthesis are described. We also describe the potential use of microreaction system for polymer particle and membrane synthesis. A description of how it would be possible to use this technology to prepare larger quantities of polymer compounds is also given.