Cataract is considered a significant global health problem and is the most frequent cause of visual impairment. Aim: this study aimed to develop postoperative self- care guideline for patients undergoing cataract surgery through the following: (1) Assessment of post operative self- care knowledge for patient undergoing cataract surgery. (2) Developing postoperative self-care guidelines for patients undergoing cataract surgery. (3) Validating the developed guideline through reviewing by experts. Design: A descriptive design. Subjects: 150 adult patients undergoing cataract surgery were included in the study. Tools for data collection: I- Patient's postoperative cataract surgery self- care knowledge assessment questionnaire. II- Patient's observational checklist for eye medication administration. Results: The present study found that, more than half of the studied patients had unsatisfactory knowledge about self care after cataract surgery. 78.0 % of the studied sample had inadequate practice regarding eye medication administration. The conclusion: Information about eye hygiene and activities of the daily living are the most prevalent needed information. Moreover, most of the studied subjects need information about administration of eye ointment and eye drop. The postoperative self–care guideline for patients undergoing cataract surgery was developed by the researcher according to patients' need. Recommendations: Health education program should be prepared for the patients undergoing cataract surgery and their families about disease management, postoperative care and prevention of cataract surgery complications.