Fluorescence from dye-labeled protein adsorbed at a solid-liquid interface was monitored with a remote interfacial chemical sensor utilizing a single optical fiber. Evanescently excited and collected fluorescence obtained using the sensor showed that adsorption of protein onto the fiber core sensing surface from a flowing solution was detected. The results demonstrate that protein adsorption can be remotely detected and monitored with time. It is anticipated that this approach will be extended to the sensing of specific surface adsorbed molecules. © 1986.