Hexamethylmelamine (HXM) is one of the substituted melamines derived from cyanuric chloride [1]. Previous studies with HXM have shown activity against small cell carcinoma of the lung, when it was given as a single agent [2, 3]. Because of relatively mild bone marrow toxicity, HXM was subsequently given in combination with other drugs and/or radiation therapy, in order to improve the therapeutic results. In this paper, our experience with HXM in treatment of small cell carcinoma of the lung is summarised.