The effect of nitrogen rate on cotton fruiting and boll setting period was studied. Five N levels (0, 40, 80, 120, and 160 kg/ha) were evaluated in a randomized complete block design with two replicates. Five plants per experimental plot were randomly marked to register daily blooms and open bolls production. Lack of N fertilization delayed the appearance of the first white bloom and shortened blooming and boll setting period. Nitrogen showed a positive relationship with the blooming period length and plant fruiting capacity. Appearance of first open bolls and length of the open bolls production period were not N affected.