There are two types of pronominal elements for marking subject and object in Galeya (an Oceanic language spoken on Fergusson Island, Papua New Guinea): those that occur independently (full pronouns), and those that must be attached to verbs. As the latter show characteristics shared by both pronouns and agreement affixes, they can be considered to be pronominal clitics. Although the distinction between pronominal clitics and agreement affixes has not always been made explicitly in previous studies of Oceanic languages, it is important for the analysis of the sentence structure of Galeya, in which both types of pronominal elements are present. If we assume that one type of pronominal element is an independent pronoun and the other is an agreement affix, the former should be an argument. If, on the other hand, we take the former to be an independent pronoun and the latter a pronominal clitic, the clitic is taken to be an argument and the independent pronoun an adjunct. By applying certain tests, it is determined that the subject and object markers attached to verbs are grammatical agreement affixes rather than pronominal clitics. This analysis leads us to the conclusion that the word order in Galeya is SOV, the same pattern as is found in neighboring languages.