The F + CH3SSCH3 reaction has been studied by He I photoelectron spectroscopy and is seen to proceed via two competing routes, a hydrogen atom abstraction channel to generate the CH3SSCH2 radical, and an adduct channel, where the adduct unimolecularly decomposes to generate CH3SF and CH3S. A weak broad band with adiabatic and vertical ionization energies of 7.00 +/- 0.07 eV and 7.45 +/- 0.03 eV,respectively, appearing at short reaction times, has been assigned to the first photoelectron band of CH3SSCH2. Two other photoelectron bands appearing early in the reaction, with measured adiabatic ionization energies of 9.26 +/- 0.03 eV and approximate to 9.4 eV have been assigned to the CH3S radical and tentatively to CH3SF, respectively. SF2 and CH3 are also observed in the reaction and are explained as the products of the secondary reaction F + CH3SF. Ab initio calculations which include full geometry optimizations have been performed on CH3SSCH2 and CH3SF and their lowest-lying cationic states, and the adiabatic and vertical ionization energies obtained are consistent with the above assignments. The structures, and bonding in CH3SSCH2 and CH3SF and their cations are also discussed.