The formation of ethyl carbamate (EC) in wines was studied together with the determination of urea and ammonia in wines. The formation of EC in model wines added with 0.25-5.00 mg/l urea was increased with increasing temperature and heating time at thermal treatment, and also with increasing amount of urea added. A clear relationship was observed between the amounts of urea added and EC formed. The amount of EC formed was larger at higher pH (4.00) than at lower pH (2.50). The EC was also formed in table wines on heat treatment, and the amount of EC formed was markedly larger in red wines of high pH than in white wines of lower pH, though a clear relationship was not observed between EC formation and urea content. Contents of urea and ammonia and EC in Japanese wines were discussed.