This paper presents rhythmic syncope in Mojeño Trinitario, an Arawak language spoken in lowland Bolivia. In this language, every vowel that is in a weak prosodic position can syncopate. The syncope pattern of Mojeño Trinitario is remarkable for several reasons. First, it involves a regular, categorical and complete deletion rather than a statistical reduction of vowels. Second, it applies similarly to words with either of two stress patterns: iambic words, which make up the great majority of words, and trochaic ones, much less numerous. Third, a great variety of consonant sequences are the result of syncope, and syllabification applies again after syncope. Fourth, rhythmic syncope actually underapplies: almost half of the vowels that are in a position to syncopate are maintained, and vowel quality plays a statistical role in immunity to syncope. Fifth, due to a rich morphology and a set of complex phonotactic rules applying sequentially, syncope leads to extreme opacity. The data presented in this paper in a theory-neutral way contribute to the typology of rhythmic syncope. It will also be of interest to phonologists considering constraint-based vs. derivational models of phonology.