Thematization, the relative frequency of a discourse referent, and topicalization are conceptualized as related discourse functions. In a probe recall experiment, a word with a thematized referent was a better recall probe than a word with a nonthematized referent. Also, an agent noun was a better prompt than a recipient, and this semantic variable interacted with topicalization so that a semantic recipient was a better prompt when it was topic than when it was comment. In a second experiment, subjects' choice between semantically equivalent active and passive sentences was influenced by thematization. Thematized nouns were chosen as topics more often than nonthematized nouns, and nouns used as paragraph titles were chosen as topics slightly more than non-title nouns. It is suggested that twin discourse functions are served by thematization and topicalization, the former providing stable referential focus and the latter providing monentary referential focus. (Author)