8-Azaadenines have been recently proposed as a novel promising class of adenosine A1 receptor antagonists. A QSAR study on 45 derivatives, synthesized in our laboratory as antagonists for A1 receptor, is described here. The use of the CODESSA program allowed obtaining a quite simple equation capable of correlating the structural features of these ligands to their activity toward A1 receptor. The model was investigated for reliability and stability by using statistical analysis criteria stricter than usual. Particular care was put in defining the chemical space where the model gave reliable predictions. The model allowed the identification of relevant structural features required for the interaction with the A1 receptor, enabling the prediction of activity of molecules belonging to focused virtual libraries.