Fluorescence is one of the few methods that allow one to observe interactions between very low concentrations of biological species in real time. Fluorescence can measure parameters such as the diffusion of a protein, its movement through a cell or other medium, and its association with other biological molecules. The purpose of the Biological Fluorescence Subgroup is to share insight into fluorescence-based methods and analysis. Fluorescence methods are very versatile and can be applied to simple molecules in water to complex species in living cells. Subgroup discussions highlight these diverse systems as well as the different methods to best understand them. The fluorescence Subgroup meets once a year at the beginning of the Biophysical Society Annual Meeting. The Subgroup meeting usually highlights a particular fluorescence method giving the history of the method and its use and application. Speakers include established investigators and junior scientists. Additionally, two students are selected to give short, 10-minute talks about their thesis research. These students are selected from the SRAA applicants. The meeting will also honor the winners of the Gregorio Weber Award and the Young Fluorescence Award.