The article deals with the numerical modelling of heat and mass transfer in the counterflow wet-cooling tower fill. Due to the complexity of this phenomenon the simplified model based on the set of four ODEs [1] was chosen. The used approach is generally applicable to the simulation of the distribution of moist air temperature. water temperature, specific humidity of air and water mass flow rate. Evaluation of the distribution of heat and mass sources is also done. Boundary condition for outlet water temperature are based on experimentally obtained Merkel number correlation. Numerical solution of chosen model was performed using Dormand-Prince method combined with shooting method. Results are compared with data available in the literature. and Obsahuje seznam literatury