In this paper the authors present the results on yield and soil losses obtained when different methods of seedbed preparation were experimentally compared on the main soil types of the state of São Paulo for the corn, cotton, and soybean crops. Based on the yield data it is concluded that there was no advantage in performing two plowings instead of one, unless the land was infested with weeds difficult to extirpate, such as nutgrass and Bermuda grass. For seedbed preparation the conventional plowing method was superior to subsurface plowing, disk harrowing, furrowing only along the rows, and hocing. Treatments that promoted the greatest soil breaking or left the smallest amount of crop residues on the soil surface, induced the biggest erosion. Seedbed preparation by plowing or subsurface plowing reduced substantially the soil losses caused by erosion when compared with preparation by means of two plowings or by the conventional moldboard plowing.