Eleven experiments were carried out in four types of soils in the State of São Paulo (Brazil) to study the effects of different levels and times of application of N on cane and sugar production per hectare and kilograms of sugar/ton of cane. The levels utilized were 60, 120 and 180 kg/ha of N (ammonium sulphate), and the times of application were: (a) total quantity at two months after planting, (b) total quantity at eight months after planting and (e) split application at two and eight months. Significant increases in sugar production were obtained in three, one and four experiments, respectively for these times of applications. The cane production was increased in more experiments (six, four and five, respectively). The sugar content (kg/ton of cane) decreased with the larger doses of application in some experiments. A combined analysis of seven experiments conducted in four consecutive years, in two soils (Latosol Roxo and Ortho Dark Red Latosol), showed that: a) All three methods and the levels applied increased sugarcane yield; b) The sugar content, decreased with N applied at eight months; c) The sugar production per hectare increased with N applied at two months and split; and d) Considering the prices of nitrogen sugarcane at the ratio of 1:60, 1:70, 1:80, 1:90 and 1:100, the economic levels of application varied between 103 and 86 kg/ha of N.