Despite the growing market of the <<Arbequina>> cultivar of green table olive. there are some trobles related to the low acidity and relative high pH values in the finished product. A comparative study has been carried with this cultivar in spontaneous and controlled fermentation, using strains of lactic bacteria isolated from marketed samples. wich has been identified allways as Lactobacillus plantarum. Starting from the main physical, chemical and microbological parameters dettermined in the experiences, some changes in the usual technique of fermentation for the <<Arbequina>> olives are proposed.