This master’s degree thesis focuses on developing a microfluidic Lab-On-A-Chip designed by using a commercial computer graphic CAD software called Rhinoceros and fabricated by employing a 3D printer (OBJECT 30 PRIME by Stratasys) based on the poly-jet technology. This microfluidic device manages to perform at a microscale level the free-flow electrophoresis that is indicated through its acronym µFFE. In particular, it is composed of a microfluidic chamber, some inlets in which sample and buffer solutions are pumped by using an automatic pumping system, some outlets from which the separation products are collected after the electrophoresis process. Different design solutions were analyzed and some attention was dedicated to realize excellent standard fluidic connectors on the back of the chip.