This study examines the role of pitch and final lengthening in German intonation phrase boundary (IPB) perception. Since a prosody-related ERP component termed Closure Positive Shift (CPS) reflects the processing of major prosodic boundaries, we combined ERP and behavioural measures (prosodic judgement task) to systematically test the impact of sole and combined cue occurrences on IPB perception. In two experiments we investigated whether adult listeners perceived an IPB in acoustically manipulated speech material that contained none, one, or two of the prosodic boundary cues. Both ERP and behavioural results suggest that pitch and final lengthening cues have to occur in combination to trigger IPB perception. Hence, the combination of behavioural and electrophysiological measures provides a comprehensive insight into prosodic boundary cue perception in German and leads to an argument in favour of interrelated cues from the frequency (i.e., pitch change) and the time (i.e., final lengthening) domain.