In the present study, we investigate site selectivity of (multiple) hydrogen loss induced by free electron attachment to purine derivatives. Like for the pyrimidines here efficient hydrogen release is also observed upon low-energy electron capture. By utilizing partially deuterated or methylated derivatives of adenine, we show that the formation of the dehydrogenated parent anion (M–H)− below 1.4 eV can be ascribed predominately to hydrogen loss from the N9 site. However, the (M–H)− ion yield shows a strong influence on the functional groups attached to the opposite site of the N9 position. By means of quantum chemical calculations, we ascribe this result to a change in the electrostatic potential distribution for the different compounds. We also present site selectivity for the formation of (M–2H)− and (M–3H)− anions formed upon electron attachment to adenine.