Background: Rheumatoid arthritis is a common health problem, as it is a systemic autoimmune inflammatory disease, causing synovitis in multiple joints especially hands and legs, joint destruction and graduate disability. Study aim: this study aimed to assess the level of knowledge about the disease in patients with Rheumatoid Arthritis. Design: A descriptive design was used in this study. Setting: This study was conducted at the rheumatoid clinic in Suez Canal university hospitals. Sample: A purposive sample of 67 patients with rheumatoid Arthritis were included. Tools: A structured interview questionnaire consisted of four parts: Part (1): Demographic characteristics, Part (2): Medical history, Part (3): Associated comorbid diseases and Part (4): patient's knowledge level about disease. Results: the results in this study revealed that: 56.7% had unsatisfactory level of knowledge about disease and its treatment. There was high statistical significant difference between knowledge with relation to residence and income. Conclusion: the study concluded that; having unsatisfactory level of knowledge about disease and its treatment. There was high statistical significant difference between knowledge with relation to residence and income. Recommendation: Educational guidelines for patients with rheumatoid arthritis to improve their knowledge level was recommended.