Postoperative delirium is one of the most common cognitive disorders facing the geriatric patients undergoing surgery. Objective: To identify factors associated with postoperative delirium among geriatric patients. Settings: The study was carried out in three general surgical units at The Main University hospital and one surgical unit in Health Insurance hospital in Alexandria. Subjects: 100 surgical geriatric patients were included in the study aged 60 years and above, had normal cognitive function, had no depression, received general anesthesia and the duration of their operation not exceeding 4 hours. Tools: Five tools were used to collect data through patient's interview and observation namely Socio-demographic and Clinical Data Structured Interview Schedule, Short Portable Mental Status Questionnaire, Geriatric Depression Scale-Short Form, Visual Analog Scale and Delirium Observation Screening Scale. Results: Nearly one quarter of the surgical geriatric patients suffered from postoperative delirium and the main factors associated with delirium were age, marital status, level of education, physical status and clinical data of the geriatric patient, length of hospital stay, hospital environment and level of anxiety pre and postoperatively. Also, type and duration of operation affected significantly the occurrence of postoperative delirium. Conclusion: Postoperative delirium is a common problem among surgical geriatric patients. Many factors are associated with postoperative delirium either pre, intra or postoperatively. Recommendations: Careful assessment of patient's cognitive status on admission to the surgical units of hospital, active participation of family in geriatric patients' plan of care and providing a safe environment.