Listeners posses a remarkable ability to attend to one of two speakers speaking at the same time (simultaneous speakers). The present research studied the role of speech rhythm involved in this process. In two experiments with the Coordinate Measure Response Corpus, listeners were asked to attend to one of two simultaneous speakers. In Experiment I native and French accented speakers of English were paired and in Experiment II resynthesized speakers with assumed durational syllable characteristics of native English and nonnative English (spoken be French) were paired. English and French native listeners took part in the experiments. Results from both experiments revealed that both English and French listener groups were better at attending to native English speakers (Experiment I) or to speakers who had English durational syllable characteristics (Experiment II). We argued that rhythmic durational differences between the speakers can enhance speaker segregation ability of listeners.