The work describes the constituent structure of the simple sentences of the Tausug language spoken principally on the island of Jolo. The simple sentences of Tausug language are classified as predicative or non-predicative. Predicatives are subdivided on the basis of their immediate constituents into situational, definite, and indefinite sentences. The same sentences are subdivided on the basis of the heads of their predicates into verbal and non-verbal. The non-predicatives are categorized into existential, meteorological, descriptive and temporal. It was found out that some roots, especially those used to form adjectives, have abstract nominal meanings. It also points out that the terms "subject" and "predicate" are used in this study as syntactic labels for the two ICS of predicative sentences, and that these terms should not be misconstrued as synonyms of the terms "topic" and "comment" respectively.