A simple, efficient, and novel method is developed for the synthesis of phosphoroamidates via an Atherton–Todd coupling reaction of amines with dialkyl H-phosphite using trichloroisocyanuric acid as an efficient and safe reagent. Treatment of amines with dialkyl H-phosphite and trichloroisocyanuric acid under base-free conditions gives phosphoroamidates in moderate to good yields. The reaction proceeded effectively to afford the corresponding phosphoroamidates via a dehydrogenative coupling of H-phosphonates with amines. This method is easy, rapid, and good-yielding for the synthesis of phosphoroamidates.