Recent evidence suggests that phonological short-term memory (STM) tasks are influenced by both lexical and sublexical factors inherent in the selection and construction of the stimuli to be recalled. This study examined whether long-term memory (LTM) influences STM at a sublexical level by investigating whether the frequency with which one-syllable nonwords occur in polysyllabic words influences recall accuracy on two phonological STM tasks, nonword repetition and serial recall. The results showed that recall accuracy increases when the stimuli to be recalled consist of one-syllable nonwords that occur often in polysyllabic English words. This result is consistent with the notion that LTM facilitates phonological STM at both a lexical and sublexical level. Implications for models of verbal STM are discussed.