The aim of our study was to investigate P wave dispersion (Pwd), QT corrected QT (QTc), QT dispersion (QTd) and corrected QT dispersion (QTcd) intervals in subarachnoid haemorrhage. Thirty-five subarachnoid haemorrhage patients (Group S) and 35 neurologically normal patients (Group C) were included in this retrospective study. The standard 12 derivations of the electrocardiograms of all patients were analysed and Pwd, QT and QTd intervals were measured. QTc and QTcd intervals were determined with the Bazett formula. There was no significant difference between the study groups according to demographic characteristics, hypertension and diabetes mellutus incidences (P > 0.05). The Pwd, QT, QTc, QTd and QTcd durations of Group S were significantly longer than those of Group C (P < 0.001). Subarachnoid haemorrhage patients may have a higher likelihood of arrhythmia during anaesthesia and in intensive care due to extended QTcd and Pwd durations.