Fluorescent silver nanoclusters (Ag NCs) have been bio-labeled to bovine serum albumin (BSA) protein by wet chemistry. The conformational changes of protein were studied using circular dichroism spectroscopy. The spectroscopic and chemical properties of these BSA-Ag NCs are explored to study their chemical sensing behavior. These NCs exhibit an intense fluorescence peak at 650 nm. Fluorescence behavior of Ag NCs has been explored for sensitive and selective detection of hydrogen peroxide.