This paper presents an analysis of control phenomena within the theoretical framework of Distributed Morphology developed by Halle and Marantz（１９９３）and others. It will be argued that anaphors, pronouns, and PRO are variants of an atomic element PRONOUN, whose morpho-phonological shapes are determined in accordance with its features and the syntactic environment in which it occurs. On this view, PRO is regarded as a Caseless PRONOUN. Obligatory control is obtained when a matrix verb selects a nonfinite clause and a DP with unvalued φ-features; in this case, the relevant DP must have its φ-features valued through the operation Agree with the subject PRONOUN of the embedded nonfinite clause, whose φ-features are valued as it is thrown into syntactic computation. Thus, obligatory control is reduced to the lexical properties of matrix verbs, which are syntactically represented in terms of Hale and Keyser’s（１９９３）theory of argument structure. As a consequence of this analysis, we can dispense with PRO and the theory of control from the grammar while keeping to the traditional view that PRO and its controller are distinct lexical items.