An improved method was proposed for the preparation of carbamoylmelamine (1). Salts of 1 were obtained by the methanolysis of 2, 4-diaminotriazinylchloro-formamidinium chloride, or by the acid hydration of cyanomelamine (2). It was observed that the hydration of (2) occurred in 2N-mineral acids at 80°C, however in hydrochloric acid ammeline (3) hydrochloride was given as main product. On the other hand, in nitric acid (1) nitrate was formed in a good yield as pure precipitates directly, since (1) nitrate was less soluble than its hydrochloride. Under the best reaction conditions, (1) nitrate was obtained in 82% yield. It was concluded that the hydration of (2) with nitric acid was applicable to the simplified method for preparation of (1).