In order to evaluate the effect of Azospirillum brasilense and mycorrhizal fungi in the soil on the nutrition of the yacon crop (Smallanthus sonchifolius [(Poeppig & Endlicher) H. Robinson]), determinations of agronomic parameters and the health status of the plants were carried out, under greenhouse conditions. The tests were carried out at the time of the implantation of the culture: the propagules were inoculated with A. brasilense and with native mycorrhizal fungi, generating four treatments, including the control and the co-inoculation of the consortium of the microorganisms under study (T0: control or control without inoculation; T1: inoculation with native A. brasilense; T2: inoculation with native mycorrhizal fungi and T3: joint inoculation with A. brasilense and native mycorrhizal fungi. The results indicate that co-inoculation with A. brasilense and native mycorrhizal fungi increased plant growth in height, leaf area, biomass, dry matter and yields significantly in greenhouse production. It was determined that the application of the selected microorganisms has a plant growth promoting effect, increasing growth and productivity, greenhouse grown yacón.