Litter decomposition is a major process in nutrient recycling, despite that few studies have considered this in soil fertility management. The aim of this study was to evaluate the effect of litter decomposition and its inoculation with the fungus Mortierella sp. on soil fertility parameters in Andisols cultivated with avocado cv. Hass. Litterbags containing avocado leaves either uninoculated or inoculated were distributed around the trees. As control litter was not allowed to accumulate on the soil surface. Eighteen months later soil samples were collected just below uninoculated and inoculated litterbags and control sites. Soil pH, potassium, calcium, phosphorus, magnesium, and boron significantly increased with litter and in some sites the increase was higher with inoculation. By contrast, soil aluminum, iron, and manganese were significantly lower in the presence of litter (uninoculated and inoculated), whereas zinc was significantly higher when litter was present.