Biological flows is an interdisciplinary subject that demands an interactive cooperation of several research fields such as biotechnology, engineering, medicine, chemistry, informatics and optics. Over the years, flow visualization techniques based on image processing and analysis have been applied in an effort to make the invisible visible with the help of experimental and computational technology. Hence, flow visualization techniques have become an indispensable tool to understand the flow behavior of several kinds of biological fluids (e.g. DNA solutions, blood and other physiological fluids) in living systems and biomedical devices. Doppler ultrasound and magnetic resonance imaging (MRI) are the most commonly used medical instruments to investigate physiological flow both in vivo and in vitro. However, due to their poor spatial resolution, it is difficult to obtain quantitative flow information. In recent years, as a result of advances in computers, optics, fluorescent probes and image analysis, several new visualization techniques have been developed in an effort to overcome such limitations. One example of success is the micro-scale particle image velocimetry (PIV) technique, which can be used to quantify the velocity field of biological flows. This thematic session will provide an opportunity to the bioengineering and biomedical community to exchange knowledge and information on the latest advances and challenges in visualization technologies and its application to biological flow research and industry. We hope to bring together researchers who are interested in the general field of flow visualization, especially in its applications to biomedical areas.