Effects of the plant growth regulators (PGRs) 2,4-dichlorophenoxyacetic acid (2,4-D, 40 mg·L -1 ), naphthaleneacetic acid (NAA, 300 mg·L -1 ) and 3,5,6-trichloro-2piridil oxyacetic acid (3,5,6-TPA, 15 mg·L -1 ) on yield, fruit size, fruit quality, fruit splitting and the incidence of creasing of ‘Nova’ mandarin were studied. All PGRs solutions were tank-mixed with ‘Bonus-npK’ fertilizer ( 5%). Sprays were applied to whole trees at 2 dates: early spray –at 13mm fruitlet diameter and late sprayat 26mm fruitlet diameter. Most fruit splitting occurred between the beginning of October and the beginning of November and the total fruit drop in the unsprayed controls, caused mainly by splitting, accumulated to 150 fruit/tree (35% of the fruit). Early spray of 2,4-D decreased fruit splitting to 25%, increased yield to 50 kg/tree compared to 37 kg/tree in the controls, increased fruit size and had no effect on the incidence of creasing. Early NAA spray, thinned fruitlets, increased fruit size, decreased splitting to 30%, decreased the incidence of creasing to 28%, compared to 36% in the controls, and had no effect on the yield. Late NAA spray did not thin fruit and had no effect on fruit size but the number of fruit harvested and yield was increased to 52 kg/tree due to split fruit drop reduction to 21%, and the incidence of creasing was reduced to only 10% of the fruit. Early 3,5,6-TPA spray caused strong fruitlets drop and only 44 fruit/tree were harvested. Late 3,5,6-TPA spray did not thin fruit, had no effect on fruit size, reduced the incidence of creasing to 22% and reduced fruit splitting to 17% , causing increase of the yield to 52 kg/tree. These data suggest that sprays of auxins on fruitlets, at time when they do not affect fruit size and do not thin fruitlets anymore, are effective for reducing fruit splitting and the incidence of creasing of 'Nova' mandarin..