Background: The chalazion is a common eyelid lesion that affects patients of all demographics Aim: The study aimed to evaluate the effect of educational guidelines on nurses’ knowledge and practices for patients undergoing chalazion surgery. Design: Quasi- experimental research design was utilized in this study. Setting: The study was carried out in ophthalmology surgical inpatient unit affiliated to Benha University Hospital Qalubya governorate, Egypt. Subject: Convenient sample of all available (n=60) nurses. Tools: two tools were used, Tool I: Self-administered questionnaire to assess nurses’ knowledge regarding chalazion, chalazion surgery, tool II: Observational checklist to assess nurses' practices. Results: The study revealed that 36.7% of studied nurses had satisfactory level of knowledge and 11.7% had competent level of practices regarding chalazion, chalazion surgery pre educational guidelines implementation, which improved post guidelines implementation to become (86.7% and 63.3%), respectively with statistically significant difference at (p≤0.05). Conclusion: Providing educational guidelines have been shown to be effective on nurses' knowledge and practices regarding chalazion, chalazion surgery. Recommendation: Continuous education and training of nurses regarding chalazion are recommended