New reaction conditions for the rapid and productive intermolecular aminochlorination reaction of alkenes using a combination of chloramine-T and a Brønstedt acid are described. Upon simple protonation of chloramine-T, conditions for a mild and selective aminochlorination are obtained. In addition, the reaction can proceed to form either of the two possible regioisomers, depending on whether a stoichiometric amount of such an acid activator or acetic acid is used as solvent. The reaction is operative for all different classes of alkenes. A total of over 50 examples is presented to illustrate this concept.