Aim: the current study aimed to evaluate the effect of Inservice training programs for nurses regarding prevention and control of COVID-19.Design: A Quasi-experimental research design was used in this study. Setting: This study was conducted on the nursing staff in the isolation hospitals affiliated with the Directorate of Health Affairs in Beni Suef, Subjects: A convenient sample consisted of 300 nurses working in isolation hospitals. Tool: Structural Interviewing Questionnaire, it was contained four parts: Part I: Nurses' demographic characteristics. Part II: Nurses' knowledge Part III: Nurses' attitude. Part IV: nurses' reported Practice about COVID-19. Results: 47.7% of the studied nurses had a satisfactory level of knowledge pre-program which improved to 93.3% post-program, 62.7% of the studied nurses had a positive attitude toward COVID-19 pre-program which improved to 98.7% post-program, and 53.3% of the studied nurses had adequate reported practice level at pre-in-service training program which improved to be 96.7% post-program, with highly statistically significant difference between pre and post-program. In addition, there was a positive correlation between total knowledge level, attitude, and total reported practice level after the program. Conclusion: Nurses' knowledge, attitude, and practice regarding the prevention and control of COVID-19 improved after an in-service training program. Recommendation: Develop in-service training programs and workshops regarding COVID-19 for nurses to increase awareness and practices for the control& prevention of covid-19