Fluids motion plays an essential role in a broad variety of natural and industrial processes. Particu- larly, those flows occurring in volumes in which at least one dimension is within the micro or nano- metric range have attracted an outstanding interest, becoming what nowadays is known as Micro or Nanofluidics. The key potential of such flows is that of isolating, manipulating and controlling the dynamic of extremely tiny volumes of fluids within a continuous phase. This feature makes such flows a unique tool to generate bubbles, drops, jets and more complex fluid structures with diame- ters in the micron and submicron ranges, which upon processing may generate micro or nanopar- ticles. The object of this proposal is to formally team up, as a Network of Excellence, internationally recognized research groups working in the area of Micro and Nanofluidics, to foster its develop- ment within the Spanish system of Science and Industry. The proposed research groups constitute a unique consortium with a well-established capacity of attacking fundamental as well as applied problems, both from the experimental and the computational side, and also with a demonstrated ability to generate novel technological solutions that can be transferred to the industrial network. The Network of Excellence will be an outstanding environment to further develop knowledge on the Fluid Mechanics of the Micro and Nanofluidic systems, but even more interesting, the Network will serve as a link to Areas in which the Microfluidics can offer solution to specific problems. Finally, the Network will disseminate the state-of-the-art of the Microfluidics through convenient advanced courses.