Introduction: Renal cysts are mostly asymptomatic and found incidentally on imaging studies. Even though asymptomatic cases doesn’t require treatment, they can cause complications like enlargement, infection and sometimes progress to carcinoma which need surgical interventions. Spontaneous resolutions are rare. Case summary: A 38-year-old man complained of pain in the right side of his upper abdomen. A left renal cyst, discovered incidentally on ultrasound, was identified with internal septations and measured 2.2*2.5 cm. The abdominal pain and cyst completely resolved within three months after administering the Homeopathic medicine Phosphorus 30c. This medicine was selected based on a comprehensive assessment of the patient's symptoms. The evidence was assessed using the USG report and MONARCH criteria. Conclusion: This case report shows the effectiveness of homoeopathic intervention in renal cyst when selected based on the totality of symptoms and individuality. This case report can contribute to evidence-based studies in this topic and further studies are encouraged.