Postoperative delirium is a complication that should not be underestimated. As it elaborates many complications that could be avoided when an accurate assessment of the risk factors and interventional measures are taken appropriately when needed.

Delirium is a variation in concentration capabilities that occurs acutely in association with a disturbed level of consciousness. Delirium is more common in orthopaedic surgery patients than in general surgery patients. As delirium ratios range from 44% to 55% in hip surgery patients, otherwise only 10%-14% of general surgery patients. Several studies were carried out and found that melatonin levels correlate with the development of delirium postoperatively. This study was conducted to determine the efficacy of administering melatonin preoperatively in patients undergoing orthopedic surgery to prevent postoperative delirium.

Inclusion Criteria:

1- Patients in good general health. 2. Baseline MDAS <13. 3. No seizure disorder.

Exclusion Criteria:

1. Patients with a neurological disorder (e.g., dementia, stroke, epilepsy).
2. Patients with a history of acute or chronic confusion.
3. Patients taking centrally acting drugs (e.g., antidepressants, antiparkinsonian drugs, sedatives, monoamine oxidase inhibitors), or alcohol abusers.
4. Patients who have medical disorders predisposing to delirium (e.g. cachexia, thyroid dysfunction, renal failure).

It has been done on all the study's contributors and workers.