A simple and efficient one-pot protocol has been demonstrated for the synthesis of 1-H-tetrazole and 1-Me-tetrazole derivatives from aldehydes under mild and metal-free conditions using ammonium azide. A number of tetrazole derivatives were obtained in moderate to high yields (75-92%) in green solvents at moderate temperature. These reactions presumably proceed via in situ nitrile formation respectively. The easy work-up and purification make this method highly valuable under mild reaction conditions.