The development of a new organ is the results of coordinated events of cell division and expansion. Fruit growth starts immediately after bloom with intensive cell division. As development proceeds, the proliferative activity of cells progressively slows down giving way to a phase of pure cell enlargement, during fruit growth and ripening. Modeling the way cell division and expansion progress together is crucial to understand the emergence of specific morphological traits ( fruit size, weight, shape and texture) and their dependence on environmental factors. Models already exist for cell division and late fruit growth ( cell expansion), but the coupling of the two processes have not been addressed yet in fruit. Here we propose a first integrated model of tomato fruit development, explicitly coupling cell proliferation and expansion. The model is used to predict the evolution of cell number, size and ages during fruit development, under different environmental conditions.