This paper reports the results of nine experiments conducted in the State of Sao Paulo on methods of application of NPK and manure for sweet potatoes (Ipomoea batatas Lam.). In two of the four trails with NPK, better results were obtained where it was broadcast before ridging than where it was placed in o furrow either under or on the top of the ridges. In the other two, the placement under the ridges showed better in the average, but the yearly results varied considerably. As the suitability of different methods of application depends on many factors, especially on the weather, the authors point to the need of farther trials and, after discussing the advantages and disadvantages of the methods studied, they suggest for the next project the inclusion of side-placement of the phosphorus, potosh and part of the nitrogen doses, the greater portion of the latter being top-dressed two to four weeks after planting. In the five trials with manure, its application between the ridges was, as a rule, inferior to both the placement under the ridges and broadcasting before ridging. Of the two last methods, the former gave better average results, but there were some indications that the latter would be more suitable either for heavy or for very light soils, in order that the organic matter improves the physical conditions of a larger volume of the soils.