Introduction: Hypercalcaemia in the presence of malignancy is commonly attributed to paraneoplastic phenomenon, particularly when associated with renal cell carcinoma. However, other causes of hypercalcaemia should be sought which can be more easily treated. Case Report: We report a case of a 54-year-old man presenting with resistant hypercalcaemia with an underlying diagnosis of renal cell carcinoma with brain metastases requiring multiple admissions for intravenous rehydration and bisphosphonates. On further investigation and surgical exploration, a parathyroid adenoma was identified, removed and confirmed on histology. His symptoms settled and biochemistry normalised, improving quality of life and reducing hospital admissions. Conclusion: This case emphasises the importance of considering primary hyperparathyroidism as a cause of hypercalcaemia in the presence of malignancy. Surgery for primary hyperparathyroidism can offer curative treatment and enhance quality of life in a palliative patient.