Iodine was found to be an efficient catalyst for the aziridination of alkenes utilizing Chloramine-T (N-chloro-N-sodio-p-toluenesulfonamide) as a nitrogen source. For example, when two equivalents of styrene were added to Chloramine-T in the presence of a catalytic amount of iodine in a 1:1 solvent mixture of acetonitrile and neutral buffer, the corresponding aziridine 1 was obtained in 91% yield. The reaction could be applied to other acyclic and cyclic alkenes such as 1-octene and cyclohexene. The aziridination of p- substituted styrene derivatives 2-5 with Chloramine-T showed that electron- rich alkenes reacted faster than electron-poor ones. Several Chloramine-T analogs were also examined and were found to give the corresponding aziridines 8-10 in only moderate yields.