A new luminescence based, highly sensitive, rapid, and easy assay method of measuring monoamine oxidase activity was developed using bacterial luciferase coupled reaction. A series of long chain aliphatic amines and bovine serum monoamine oxidase were used for the demonstration. Nonyl amine and nonyl aldehyde, the product, pair were found to be the most suitable substrate for this system. K_m value of nonyl amine was 24 μM. This luminescent method has at least 100 folds higher detectability of aldehyde product than spectrophotometric assay methods using absorption of benzaldehyde generated from benzyl amine at 250 nm wavelength.