One of the challenges of including pigs in a sustainable farming rotation is to preserve soil fertility.In fact, without a correct rotation of the paddocks, grazing pigs cause, with their normal feeding behaviour, excavations, destruction of the sward and soil structure damage, with negative influence on soil fertility. The aim of this study is to investigate soil fertility dynamics throughout one year in an organic outdoor pig farm. An on-farm study was carried out in the south of Tuscany, in Italy. The experimental design included 6 plots hosting different crop sequences. Grazing pigs were periodically moved among the plots. Soil organic C (SOC) and total N (Ntot) were selected as fertility indicators, and their contents were measured in the top 0-20-cm soil layer, in 12 dates, in the period between June 2010 and September 2011. Mean SOC and Ntot contents were remarkably different depending on the plot. However, for a given plot, they increased or did not vary during the sampling period, with exception of the sorghum plot, where a slight decrease in C content was observed. These preliminary results support the hypothesis that soil fertility is not negatively affected by outdoor pig grazing, with the cropping system adopted by the organic farm hosting this experiment.