This study reports a new microfluidic system with three integrated functional devices for pumping, mixing and separation of bio-samples by utilizing micro-electro-mechanical-systems technology. By using antibody-conjugated magnetic beads, the developed system can be used to purify and enrich virus samples such that the subsequent detection of viruses can be performed with a higher sensitivity. The target viruses were first captured by the antibody coated onto the magnetic beads by using a rotary micromixer which performed the incubation process. The viruses were then purified and enriched by a magnetic field generated by planar microcoils. The integrated microfluidic system can perform the whole purification and enrichment process automatically using a rotary micropump and appropriate microvalves. In addition, a numerical simulation was also employed to optimize the design of the microcoils and to investigate the magnetic field strength and distribution. The simulation results were consistent with experimental observations. Finally, the developed system was used to successfully perform the purification and enrichment of Dengue viruses. The detectable limit of Dengue viruses was found to be as low as 10(2) pfu ml(-1) by using this approach. Therefore, the integrated microsystem can perform incubation, transportation, mixing and purification of virus samples, possibly making it a promising platform for future biological and medical applications.