Abstract Background: Advanced nursing interventions for patients diagnosed with cancer included progressive muscle relaxation (PMR) training that has positive effects on anxiety and sleep pattern. Aim: To evaluate the effect of progressive muscle relaxation technique on anxiety and sleep pattern among newly women with breast cancer. Design: A quasi-experimental research design with a pretest-posttest was used in this study. Sample: A convenient sample of 80 women newly diagnosed with breast cancer that equally was divided into two groups. Setting: This study was conducted at the inpatient and outpatient clinic of Fayoum Oncology Center and University Hospital. Tools: Three tools were used: (I) an Interview Structured Questionnaire, (II) Spielberger State-Trait Anxiety Scale (STAI), and (III) Sleep State Self-Rating Scale (SRSS). Results: The results of the present study indicated that the mean age of the women was 46.51 ± 12.03 years. There were significant differences in anxiety score and improvement in sleep quality score after the intervention (p < 0.05) of the progressive muscle relaxation. Conclusion: The current study concluded that progressive muscle relaxation has been found to reduce anxiety and improve sleep pattern among women who are newly diagnosed with breast cancer. Recommendations: Providing an educational program to women who are newly diagnosed with breast cancer regarding progressive muscle relaxation technique and how to perform and its benefit.