Molecular probes are provided for use in fluorescence microscopy procedures for monitoring beta-secretase enzyme (BACE) activity in living cells and organisms. The probes may be useful for monitoring Alzheimers Disease-associated BACE in living cells. By fluorescing when hydrolyzed by BACE, the probes can allow for real-time spatial and temporal assessment of enzymatic activity without the need for mutated cell lines or antibodies. The molecular probes may also be used to screen libraries of potential BACE inhibitors or evaluate how external stimuli affect BACE activity.