Background: Heart failure and renal failure patients have limited physical activity and decreased quality of life. Alternate-nostril breathing is a breathing that reduces bad progression to their disease by regular practicing. Aim: Was to evaluate the effect of alternate nostril breathing exercise on heart failure and renal failure patients' outcomes. Design: Quasi-experimental comparative design was utilized 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: Four tools were used, tool I: Patients' interview questionnaire, tool II: Physiologic parameters assessment, tool III: Sleep quality scale and tool IV: Fatigue assessment scale. Results: There were highly statistical significant differences in patients' outcomes 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) which were presented by physiologic parameters, sleep quality and fatigue level. Conclusion: Alternate nostril breathing exercise has been shown significantly improvement of outcomes among heart failure & renal failure patients while renal failure patients' outcomes 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' outcomes as well as, for other patients with chronic illness.