The pitch contour of an utterance in a tone language can surface with both tonal and intonational f0 features. In this paper we set out to analyze the intonational phonology of Boro, a tone language, and establish that there are three levels of prosodic constituents in Boro: Prosodic Word, ip and IP. Prosodic Word is the domain for distribution of lexical tones. Phonological processes show that the next higher level of prosodic structure is that of the intermediate phrase. Downstepping is within intermediate phrases (ip) and does not cross ips. The highest level of prosodic constituency is the IP which is marked by both initial and final boundary tones. This study shows that in Boro intonational phonology, boundary tones and their scaling and alignment in the context of their lexical tones is more important than assigning pitch accents.