The combination of sodium periodate, potassium iodide, and sodium azide has been found to be an efficient, simple, and inexpensive reagent system for azidoiodination of alkenes. The regiospecific 1,2-azidoiodination proceeds in an anti-Markovnikov fashion to produce β-iodoazides in excellent yields. azides - alkenes - azidoiodination - β-iodoazides - regiospecific