This work presents the results and interpretations of two N, P, K, S mineral fertilizer trials on wheat (Trlticum aestivum L.), cultivar IRN-526-63, carried out in low land conditions at the Mococa Experiment Station and Guatapará Parmer, São Paulo State, in 1971. The responses observed in these trials present a big effect to nitrogen, little effects to phosphorus and potash. Every 30 kg N/ha increased 292 kg/ha the production. The use of sulphur, increased 7% the production in relation to the treatments without fertilizer. With the results of the experiments, there were computed the better quantities of N-P-K fertilizers to be applied, for the soils studied, for several relationships between wheat and fertilizers prices.