Leiomyosarcoma is an aggressive soft tissue sarcoma derived from smooth muscle cells typically of uterine, gastrointestinal or soft tissue origin. Leiomyosarcoma of soft tissue is thought to arise from the smooth muscle cells lining small blood vessels. It can also arise directly from the viscera, including the gastrointestinal tract and uterus. We present a case of large retroperitoneal leiomyosarcoma with close proximity to major blood vessels and left renal vessels involvement, for tumour excision and its anaesthetic management. A relatively long surgery with major blood loss along with the left nephrectomy made this procedure challenging for the anaesthesiologist in maintaining euvolemia and haemodynamic stability without causing acidosis, organ damage, coagulopathy and acute kidney injury. A vigilant and proactive anaesthesiologist with good communication with the surgeons is essential for successful management of complex surgeries.