Groundnut has emerged as an interesting productive alternative for farmers in the central zone of Chile. However, there are no available bacterial inoculants in this area, to promote biological nitrogen fixation in this crop. The aim of this study was to determine the effect of three different Bradyrhizobium strains on Valencia type groundnut growth and yield. A field experiment was conducted at the experimental station "El Nogal" at the University of Concepción, using a completely randomized block design. The evaluated strains were C-145, SEMIA 6144 and an isolate from the commercial inoculant, which were applied as liquid inoculants. Two uninoculated treatments were included: one with and one without nitrogen fertilization. Each experimental unit consisted of plots of 9.6 m2. At early bloom, chlorophyll content was measured, and nodule number and nodule activity were also recorded. At harvest, the biomass distribution and pod yield, seed, foliage and 1000 kernel dry weight were determined. The inoculants induced a significant increase on plant growth in comparison to uninoculated plants without nitrogen. This was expressed as leaf chlorophyll content, accumulation and distribution of plant biomass, and in seed yield and dry weight. The strain isolated from the commercial inoculant showed the best performance.