In food plants, often water is present in form of droplets deposited on the equipment surfaces, on the walls and the floor. Microbial growth can occur in these droplets especially if they contain nutritive substances like sucrose. A mathematical model was developed in order to predict the evolution of mass, temperature, sucrose concentration and water activity of a droplet of sucrose solution deposited on a solid surface. The model takes into account heat and mass transfer by convection at the air/liquid interface, radiation with surrounding walls, conduction inside droplet and solid surface as well as latent heat of vaporization. It predicts also the increasing concentration of sucrose and the associate decrease of water activity. Two drying periods are considered, first the radius of droplet surface contact remains constant and the contact angle decreases, then this angle remains constant (equal to the receding angle) and the radius tends to zero. The evolutions during drying of sucrose solutions of different initial concentrations were compared. This model could be coupled with a microbial model in which the growth rate depends both on temperature and water activity.