This work examines the use of neural networks in modelling the adsorption process of gas mixtures (CO2, CH4, and N-2) on different activated carbons. Seven feed-forward neural network models, characterized by different structures, were constructed with the aim of predicting the adsorption of gas mixtures. A set of 417, 625, 143, 87, 64, 64, and 40 data points for NN1 to NN7, respectively, were used to test the neural networks. Of the total data, 60 %, 20 %, and 20 % were used, respectively, for training, validation, and testing of the seven models. Results show a good fit between the predicted and experimental values for each model; good correlations were found (R = 0.99656 for NN1, R = 0.99284 for NN2, R = 0.99388 for NN3, R = 0.99639 for Q(1) for NN4, R = 0.99472 for Q(2) for NN4, R = 0.99716 for Q(1) for NN5, R = 0.99752 for Q(3) for NN5, R = 0.99746 for Q(2) for NN6, R = 0.99783 for Q(3) for NN6, R = 0.9946 for Q(1) for NN7, R = 0.99089 for Q(2) for NN7, and R = 0.9947 for Q(3) for NN7). Moreover, the comparison between the predicted results and the classical models (Gibbs model, Generalized dual-site Langmuir model, and Ideal Adsorption Solution Theory) shows that the neural network models gave far better results.