The French software tool AzoFert (R) is based on a complete and predictive dynamic nitrogen balance sheet to establish the nitrogen fertilization recommendation. This software tool uses modelling and measurement of the mineral nitrogen stock at the beginning of the balance in order to precisely adjust the fertilizer recommendation to the soil, climatic and cultural characteristics of the field. AzoFert (R) was tested on 65 nitrogen fertilizer trials (crop*site*year) conducted by Agroscope from 1996 to 2010 on the main arable crops and a wide range of pedoclimatic conditions. It demonstrated satisfactory prediction of the optimum dose, at least equivalent to that obtained by the corrected norms and Nmin methods. The study was conducted with an AzoFert (R) parameterization used in the north of France. Adaptation of the parameterization to Swiss conditions should allow the predictive value of the software to be increased.