This paper presents the results of two fertilizer trials comparing nitrogen sources for the tomato plant. Both were carried out at the Monte Alegre Experiment Station, on a massape type of soil. The nitrogenous fertilizers were ammonium sulfate, Nitroealcio (ammonium nitrate plus calcium carbonate), Chile nitrate and urea. They were applied as top dressing four and five times, respectively, for the first and second experiments. The results of these tests indicated that there was no significant difference between the nitrogen sourees, but on the other hand its application was highly significant when compared with the control, except for the Chile nitrate.