In this research we determined the effects of the cover of the leguminous T labialis on the soil properties. The experiment was carried out in a Valencia late orange plantation (Citrus sinensis L. Osbeck), of 22 years, in production, set out at 8 x 4 m of distance, on a clay soil characterized as ferralitic red compacted eutric, with a pH of 5,7 and organic matter of 2,80 %. A randomized block experimental design with three repetitions was used to evaluate the treatments (leguminous cover, natural cover and bare soil); each one of these is constituted by a plot of 64 m2, which included two citrus plants and their two neighboring rows. It was determined the effect of the experimental variants on the following biological, chemical and physical properties of the soil: soil macrofauna, organic matter, n water pH and the available phosphorus, soil density, density of the solid phase, humidity to field capacity, total porosity, and structural coefficient. The cover of the leguminous T labialis surpassed statistically the remaining treatments of both indicators of the macrofauna (number of individuals/m2 and biomass, g.m 2 ). It was also obtained a bigger percentage of organic matter and the P availability in this treatment. At the end of the experimental phase, the soil pH increased significantly by 0.5 while using the leguminous cover. The density reached a low value in the treatment with the leguminous cover, that was close related to an increase in the organic matter content. The cover of the leguminous T labialis favoured the productive performance of the plantation. It can be stated that the insertion of the leguminous cover in a citrus plantation constitutes an efficient alternative to the management of the agro ecosystems, and it improves substantially the soil´s physical, biological and chemical properties, without damaging the crop performances.