Background: For mothers of children undergoing cardiac catheterization, the procedure is a stressful and anxiety-inducing event. So, as part of getting moms ready for the surgery, a catheterization nurse's duties start with assessing their level of anxiety. Data suggests that mothers' worry and sleep issues are lessened by the pre-procedure information provided by CC pediatric nurses. Many techniques are available for providing information. Print materials, such as an illustrated educational guide, were used in this study. You can reduce anxiety and improve the quality of your sleep by using progressive muscle relaxation. Aim: To determine the impact of progressive muscle relaxation implementation on mothers' sleep quality and anxiety level having children undergoing cardiac catheterization. Subjects and method: Design: A quasi-experimental research design was utilized to fulfill the aim of this study. Setting: The study was conducted at the catheterization unit at Sohag University Hospital. Subjects: A convenient sample of 100 children undergoing cardiac catheterization and their mothers were randomly divided into two groups within six months. Tools: Three tools were used: Tool (I): A structured interview schedule Tool; (II) Pittsburgh Sleep Quality Index Scale, and Tool (III) Spielberger State Anxiety Scale. Results: There were significant differences and improvements in sleep quality mean scores and anxiety levels between the two groups' post-progressive muscle relaxation implementation. Conclusion: Progressive muscle relaxation implementation has a significant effect on improving mothers' sleep quality and reducing their anxiety levels. Recommendations: Provide a Training program for mothers of children undergoing cardiac catheterization about progressive muscle relaxation to enhance the quality of sleep and reduce anxiety levels. Cardiac catheterization nurses should develop an illustrated educational guide about cardiac catheterization to be used as a reference for orientation pre-cardiac catheterization procedure and disseminated to parents before discharge.