Speakers use prosodic emphasis to express the content of their message in order to help listeners to infer meaning. By measuring event-related potentials (ERPs) to semantically congruent and incongruent final words embedded in a sentential context that was emphasised or de-emphasised, we investigated whether prosodic emphasis conveyed by a sentential context leads listeners to a finer semantic analysis. The negative shift (N400) triggered by the difficulty to combine the incongruent word with the sentence representation was increased by prosodic emphasis at an early stage. Over the later stages, the amplitude of the N400 wave was increased by prosodic emphasis of the sentential context, whatever the semantic congruency of final words. As shown by the N400 wave, emphasising a sentential context affected the lexical-semantic processing of the following word. This study provides clear evidence that prosodic emphasis plays a role in the semantic analysis of sentences by inducing a deeper analysis. © 2018, © 2018 Informa UK Limited, trading as Taylor & Francis Group.