In Chamacoco (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. This article proposes a descriptive classification of Chamacoco possessable nouns and analyses the morphology of possessive inflection. Few possessable nouns have also a non-possessable form which is also discussed in this article.