Background: The patient who undergoing radical cystectomy has needs many nursing care because of alterations in the functional health patterns of elimination, health, management, cognitive, self-perception and role relationships. Aim of the study: This study aimed to assess nurse's knowledge and practice regarding patients undergoing Radical cystectomy surgeries. Research design: Descriptive research design was utilized in this study. Setting: The study was conducted at the Surgical Oncology Department at South Egypt Cancer Institute. Sample: A convenience sample including (60) nurses working at surgical oncology department who are willing to participate in the study. Tools: Structured interview questionnaire sheet, and observation checklist sheet. Results: the majority of nurses had unsatisfactory knowledge as regarding radical cystectomy surgeries. The score knowledge about specific care after procedure was higher (Mean±SD= 2.42±3.2) in compared to other items including; Radical cystectomy surgeries, nursing care before cystectomy, and general care after cystectomy. The majority of nurses were inadequate of their practice regarding postoperative instruction before discharge with (mean±SD= 33.78±3.77). Conclusion: a significant statistical difference between nurses knowledge in relation to total mean knowledge score, a significance statistical difference between nurses practice in relation to total mean practice score. Recommendations: nurses need for in- service training programs and refreshing courses to improve knowledge which will reflect into their knowledge and practice while work with patients.