In Ayoreo (Zamucoan) nouns can be divided into possessable and unpossessable. Possessable nouns are characterized by a prefixation whereby the noun agrees with the possessor or genitival modifier. In this article the possessive inflection is described in detail and a classification of possessable nouns is proposed. Possessable nouns also have a unpossessable form. The morphological relationship between the latter and the possessive inflection is discussed.