Based on experiments conducted from 1950 up to 1963 on different soil types of the State of São Paulo, the authors studied the efficiency of several phosphorus carriers, for the fertilization of sugar cane, when applied in the presence of NK at the rate of 100 kilograms of total P2O5 per hectare. The areas used were all deficient in phosphorus with pH varying between 4.5 and 6.3. Giving the value 100 to the responses to ordinary superphosphate, the average relative efficiencies of the phosphates that were used in 6 to 14 experiments were the following: thermophosphate, 107; dicalcium phosphate, 105; bone meal, 91; Olinda-phosphate, 63; Alvorada-phospha-te, 61; Araxá-phosphate, 57; phosphorous bauxite, 40. The four latter carriers are natural phosphates from different regions of Brazil. The authors also studied the influence of the soil types, as well as that of the pH and the level of available phosphorus in the soil.