The Baeyer-Villiger monooxygenase OTEMO from Pseudomonas putida ATCC 17453 has been employed as biocatalyst in the asymmetric synthesis of a set of optically active sulphoxides. Several alkyl aryl sulphides are oxidized by this biocatalyst leading to the (S)-sulphoxides. Especially for those substrates containing electron-donating groups in the aromatic ring or in the alkyl moiety, good to high enantiopurities can be obtained. OTEMO is also able to perform the kinetic resolution of racemic sulphoxides, but with low enantioselectivities. Finally, parameters that can affect its biocatalytic properties, such as pH, temperature, organic cosolvents and substrate concentration, have been tested to get a better insight into the biocatalytic potential of this hitherto poorly explored oxidative biocatalyst.