This study seeks to ﬁnd a correlation between silent pauses (SPs) in source text and the ﬂuent delivery in target text during these pauses in simultaneous interpreting from Chinese to English. Experiments have been carried out to home in on SPs by speakers to examine exactly what is going on while silences last. Two speech styles of formal speech and spontaneous speech are then taken into consideration to see whether stylistic difference yields different results in the SP–ﬂuency correlation. Two indicators are identiﬁed as the factors pointing to the dual effect of SPs: the rate of ﬂuent interpreting during SPs (Indicator One), and the rate of SP-included sentences being successfully interpreted (Indicator Two). Both the concurrent and the continuing effects are proved tenable by looking at the relations between the two indicators and different SP positions and durations. Results indicate that the possibility of both indicators is signiﬁcantly higher during speakers’ pauses at grammatical junctures; Indicator One is more pronounced during pauses of medium length while Indicator Two is more pronounced during pauses of longer length. A negative correlation between SP duration and Indicator One is found while a positive correlation between SP duration and Indicator Two is conﬁrmed. Furthermore, this study concludes that speech style does make a difference in the correlation between SP positions and the two indicators: formal speech interpreting shows clearly better regularity than spontaneous speech interpreting.