Two models simulating pollination and fruit growth in kiwifruit orchards are described. They are part of a global biotechnical model which aims at studying the effects of planting scheme, pruning intensity and thinning patterns on fruit number and size. The pollination model calculates the amount of pollen grains deposited on pistillate flowers, according to the position of the female vine and the date of anthesis. On this basis, the number of ovules that develop into seeds, and the success of fruit set given this number, are simulated in a stochastic manner. In the fruit growth model, we assumed that the effects of seed number and crop load act at any time in a multiplicative manner on a reference relative growth rate. These two models make it possible to simulate the between-fruit variation in fruit size.