The simultaneous evaluation of the PES and valence synchrotron photoionization studies complemented by the results of quantum chemical calculations offers unusually detailed insights into the valence ionization processes of small covalent molecules. Thus, methyl thiochloroformate, ClC(O)SCH3, has been investigated by using results from both photoelectron spectroscopy (PES) and synchrotron radiation in the valence energy range. In an additional series of experiments, total ion yield (TIY) and photoelectron-photoion coincidence (PEPICO) spectra have been recorded. Furthermore, the relative yields for ionic fragments have been determined as a function of the photon energy. Vibronic structure has been observed in the TIY spectrum recorded in the synchrotron experiments. The photodissociation behavior of ClC(O)SCH3 can be divided into two well-defined energy regions.