Background: Sickle cell disease and sickle cell anemia are serious, inherited conditions affecting the blood and various organs in the body. Sickle cell anemia is more common in people whose origins are sub-saharan Africa, India, Saudi Arabia and Mediterranean countries. Aim of the study: to evaluate the extent of knowledge and practice of patients with sickle cell regarding the disease and preventive measures of its pain crisis. Material and method: descriptive correlative design was used in the study. The subjects of the study consisted of 73 adult sickle cell anemic patients in hematological department and outpatient clinic at Assuit University Hospital. Structured questionnaire using of open ended and closed ended questions was used based on literature review. Results: More than half of patients 54.8 % had hemoglobin level of 8 mg/dl. Majority of patients 86.3% had knowledge score more than 70% and nearly half of them 50.7% had satisfactory practice score ranged from 60-70%. Conclusion: although patients' knowledge level in this study was high, the practical score level of nearly half of patient was satisfied. Recommendation: conduct continuing education for primary health care professionals to improve their ability to care for, and provide guidance to patients and their families with sickle cell disease.