Background: Leg muscle cramp that occur during hemodialysis result in shortening of treatment or reduction of fluid removal which lead to inadequate clearance of waste products which significantly increase mortality risk. The aim of the study: was to evaluate the effect of moist heat application on leg muscle cramp for patients undergoing hemodialysis. Research design: A quasi-experimental design was used. Settings: this study was conducted in the hemodialysis unit at Beni-Suef University Hospital and General Nasser Hospital. Subjects: A purposive sample of (60) patients who admitted to the hemodialysis unit with leg muscle cramps were included. Data collection Tools: three tools were used for data collection. Tool I: Patient structured interview sheet, Tool II: the cramp questionnaire chart and Tool III: The Pain Numeric Rating Scale. Results: The study findings revealed that there was statistically significant difference was found between study and control groups with higher reduction in the total mean score of pain from 6.78 ±1.6 to 2.34±0.9 among the study group who received moist heat application. Conclusion: this study concluded that moist heat application was an effective nursing measure in reducing the pain intensity of leg muscle cramp for patients undergoing hemodialysis. Recommendations: the study recommended that: Continuing education for nurses must be provided to improve their knowledge and practice regarding non-pharmacological methods such as moist heat application and its effect on reducing the pain intensity of leg muscle cramp for patients undergoing the hemodialysis