In 1993 and 1994, trials were carried out to optimize the use of CPPU on Actinidia deliciosa. CPPU treatments were carried out at different times (2, 3, 5 and 7 weeks after full bloom), using different concentrations (0, 0.5, 1, 2.5, 5, 10 and 20 ppm), utilizing both a manual sprayer and a tractor-mounted atomizer; also repeated CPPU applications.were tested. All CPPU treatments increased the fruit weight and consequently the yield per vine with respect to the control. The increase in fruit weight was positively correlated to CPPU concentration up to 5 ppm, thereafter higher CPPU concentrations did not produce any further significant increase in weight. CPPU application greatly influenced fruit dry weight which was negatively correlated to the time of CPPU application. The repeat application of CPPU caused an increase in fruit fresh weight similar to the single application made with a concentration equal to the sum of the two used for the repeat application, but it resulted in a lower fruit dry weight. CPPU increased the percentage of fruits with a protruding distal end, with an intensity positively correlated to CPPU concentration; moreover, at the higher concentrations it increased the maximum/minimum diameter ratio of the fruit. Elimination of dripping during CPPU application, by use of an atomizer, reduced the percentage of fruits having a protruding distal end. The earliest CPPU treatment caused a rapid increase in soluble solids and a decrease in flesh firmness with respect to the control, resulting in early fruit ripening. During cool storage in normal atmospheric conditions (0±0.5 °C, R.H. < 95%), the soluble solids in the fruits increased in all the treatments and after 5 months of storage they were consistently higher in the control and early treated fruits. At the same time flesh firmness decreased with late treated fruits having lower values. The results indicate that with a correct use of CPPU in terms of application time, amount and modality of distribution it is possible to combine the positive influence of CPPU on fruit size and yield per vine with lack of negative effects on shape, quality and storability of fruits, by treating early and using relatively low concentrations of CPPU.