A trial in Rio Negro Valley, Argentina studied the thinning effect of BA+GA₄₊₇ (Accel), Pelargonic acid (Thinex), a combination of Carbaryl+NAA and Accel+NAA in apples cvs. 'Fuji', 'Royal Gala' and 'Red Delicious'. In 'Fuji', Accel (267 ml/ 100 l) was applied at 5 and 10 mm fruit diameter (FD). Pelargonic acid (312.5 ml/100 l) was sprayed at 60 and 80% full bloom; the mix Accel/Carbaryl (267 ml/100 l + 120 gr/100 l) was applied at 13 mm of FD and NAA/Carbaryl (5 mg/l + 60 gr/ 100 l) was applied at 13 mm FD. A Control treatment was also included in each experiment. Same treatments were applied in both 'Fuji' and Gala but in the later Pelargonic acid was sprayed at full bloom. In 'Red Delicious' the only chemicals tested were Accel (267 ml/100 l) applied at 7 and 10 mm FD, and Pelargonic acid sprayed at 80% full bloom. In 'Fuji' and 'Royal Gala', Accel/Carbaryl resulted in better fruit thinning but differences with Accel were not significant. Pelargonic acid was effective only in 'Fuji'. In 'Red Delicious', Accel achieved excellent thinning but that was not the case of Pelargonic acid. Although no significant, there was a trend in the reduction in spurs that set 3 or more fruits with the Accel and the mix Accel/Carbaryl in 'Fuji' and 'Royal Gala'. In 'Fuji', fruits treated with Accel and the combination Accel/Carbaryl were larger and had high lenght/diameter ratio.