Heart failure and renal failure patients have many problems as pain, muscle cramps and fatigue; alternate-nostril breathing is a type of breathing practice that has beneficial effects on pain level in healthy and diseased people. Aim: Was to evaluate the effect of alternate nostril breathing exercise on heart failure and renal failure patients' pain level. Design: Quasi-experimental comparative design was utilized in this study to achieve the aim of this study. Setting: The study was conducted in cardiac care unit and hemodialysis unit at Benha University Hospital. Sample: Purposive sample (70 heart failure patients &70 renal failure patients) was included in this study. Tools: Two tools were used, tool I: Patients' interview questionnaire and tool II: Visual analogue pain scale. Results: There were highly statistical significant differences in pain level between pre ANB intervention as compared to after 1 month and 3 months intervention among heart failure and renal failure patients as (p≤0.001). Conclusion: Alternate nostril breathing exercise has been shown to be effective on heart failure & renal failure patients' pain level while renal failure patients' pain level have been shown higher improvement. Recommendations: Hospitals are recommended to implement the alternate-nostril breathing exercise alongside other treatments to improve heart failure & renal failure patients' pain level as well as, for other patients with chronic illness