Relatively little instrumental work has been done on the intonational structure of American Indian languages. This study investigates the intonation of Chickasaw, an American Indian language belonging to the Muskogean family, following Pierrehumbert's [The Phonology and Phonetics of English Intonation (MIT, Cambridge, MA, 1980)] intonation framework. Preliminary results suggest certain interesting intonational features in Chickasaw. Declarative intonational phrases with neutral subject--object--verb word order are marked with a high boundary tone, whereas interrogative intonational phrases are signaled with a low boundary tone. In both types of phrases, a high nuclear pitch accent docks onto the right-most heavy syllable in the verb, where heavy is equivalent to CVV, CVC, or CV in a metrically prominent position. Data also show that an intonational phrase in Chickasaw consists of one or more accentual phrases. Accentual phrases consisting of a single word begin with a low tone, and receive a high tone both on the second syllable and the final syllable of the phrase: LHH pattern. The initial low tone of the accentual phrase is typically not realized in words with fewer than three syllables. Accentual phrases consisting of more than one word and the effect of focus on intonation will also be considered.