Calcific myonecrosis is a rare, late complication of compartment syndrome in the lower extremity. In this condition an entire single muscle of the leg is replaced by a fusiform mass with central liquefaction and peripheral calcification. Calcific myonecrosis presents a diagnostic dilemma to the clinician; it has to be considered in the differential diagnosis of a calcifying soft tissue tumour in the lower extremity. The purpose of this report is to highlight the importance of recognition of the lesion and its key clinico-pathological presenting features leading to appropriate management. We describe the unique presentation, diagnosis and surgical management of calcific myonecrosis involving only the flexor hallucis longus muscle of the leg in a middle-age adult. We found MRI Scan as the most useful method of investigation. Diagnosis can be confirmed by yellow-brown paste like material within the lesion intra-operatively or by aspiration and further by histology. We recommend complete excision of the lesion and closure of the wound with compression dressing, to avoid secondary infection.