The onset of delirium is frequent in elderly patients who sustain hip fractures. The purpose of this study was to characterize different patterns of preoperative and postoperative delirium, to study factors associated with preoperative delirium and to evaluate the possible different outcome of these patients. This retrospective study comprised 281 elderly patients with hip fractures undergoing surgical fixation. Data collection included age, sex, length of stay, type of fracture, cognitive status by mini mental state examination (MMSE), assessment of possible delirium by the confusion assessment method (CAM) and functional outcome assessed by functional independence measure (FIM). A database search was conducted to identify whether delirium onset occurred prior to or following surgery. About 31% of the total sample developed delirium. Delirious patients tended to be more disabled (P = 0.03) and cognitively impaired (P = 0.018), compared with non-delirious patients. Most delirious cases (53%) had their onset in the preoperative period. Patients with preoperative delirium were older (P = 0.03), had a lower prefracture mobility (P < 0.01), impaired cognition (P = 0.04) and showed an adverse functional outcome in terms of FIM score. Regression analysis showed that prefracture dementia, prefracture mobility and low MMSE scores were strongly associated with higher probability of having preoperative delirium, with no additional effect of other variables. It is concluded that preoperative delirium should be viewed as a separate entity with unfavorable nature and adverse outcome. Careful preventive measures and better treating strategies should be employed to avoid this clinical condition.