The experiment was conducted at the Citrus Experimental Station located in Bebedouro, São Paulo State, Brazil, to verify the relationship among flowering, fruiting and yield of ´Pera´ sweet orange trees grafted on ‘Cleopatra’ mandarin. The plants were subjected to the following treatments: thinning of flowers, thinning of young fruits, late harvest, and regular harvest of fruits (control). Fruit production on subsequent years and fruit quality was also evaluated. A randomised block design with five replications and three plants per plot was used. The first year fruit production was highest in the control followed by late harvest treatment, whereas the other two treatments yielded much less fruits. The treatments with thinning of flowers and young fruits reached, in 1996, the ideal technological characteristics of fruit quality later than the regular and later crop treatments. The production of the second year was higher in plants subjected to thinning of flowers and fruits probably because, in such plants, the flowers were not submitted to competition with fruits. Another possibility to be considered is biennial production. Significant differences of fruit quality were not observed in 1997. The cumulative production was highest for the regular harvest treatment, mainly due to the first year (1996) production.