The objective of this study was to evaluate the effect of cultivated plant-forest species richness on the sustainability of agroforestry systems in the south Peruvian amazon. From a population of 150 producers we selected 50 and recorded information of 82 variables through surveys with structured questionnaire, field observations and field sample collection in the agroforestry sites. We grouped together five different types of agroforestry systems and evaluated their sustainability by elaborating economic, ecological and sociocultural indicators. Results were analyzed with correlations across the calculated sustainability indexes and the quantity of plant species cultivated in the sites. We found that the economic indicator of the V agroforestry system of 7.5 years with a combination of 3 perennial crops, 6 forestry species and one palm was not sustainable because was below two and the systems I, II, III and IV were sustainable due to more than 10 years of production and more diversity of plant species. There was a direct and positive impact on the sustainability of agroforestry systems based on the quantity of cultivated plant species, in which there were higher indexes in the sites with more plant species.