The effects of boron on the behaviour of sugarcane (plant-crop and first ratton crop) var. CB 41-14 were studied in a trial pot with increasing doses of this micronutrient to Ibitiruna soil from Piracicaba, SP, considered poor in boron content. The boron applied did not increase cane growth nor sugar content, but 8 ppm B reduced both cane and sugar production. Chemical analysis with leaves 5 months old revealed increasing boron contents according to the amounts given to the soil. With leaves 8 months old, the B levels were lower and non selective with respect to the boron amounts applied. The best time to sample leaves for B analysis seems to be 5 months, in the conditions of the study.