This work was carried out in pots in order to study the fertilizer effect of urea in face of the ammonium nitrate, ammonium sulphate and urea plus sulphur, being this last one under two forms: potassium sulphate and calcium sulphate. A "tabuleiro" soil, from Rio Largo, Stade of Alagoas, Brazil, was used. The experiment took place at the Escola Superior de Agricultura "Luiz de Queiroz", University of São Paulo, located in Piracicaba, State of São Paulo, Brazil. Corn plant (Zea mays L.) c.v. Piranão was used as test plant. The evaluation parameters was the content of nitrogen of the plants. In a general way all of the fertilizers tested were similar in what concern to the disponibility of the nitrogen to the plants. One can expected that urea, when conveniently applied to the soil, will prove to be a good source of nitrogen as any other nitrogen fertilizer tested.