This paper aims to investigate the relationship between the use of formulaic sequences (FSs), speaking ability and speech fluency. Formulae form a considerable portion of native-speakers' speech and mastering them helps learners to appear more native-like. In this study 41 learners of English were interviewed and their speech fluency, level of proficiency and also the frequency of their use of FSs were measured and statistically analyzed. The results of frequency and correlation analyses show that among the seven categories of FSs proposed by Ohlrogge (2009), "Personal Stance Markers" and "Transitions" show significant correlation with speaking scores. In addition, discriminant function analysis shows that the frequency of the use of these two categories of FSs can predict the learners' overall speaking scores better then their speech fluency. The applications and implications of the findings for language teaching and phraseology are discussed.