Primary sarcomatoid urothelial carcinoma of the ureter with heterologous elements is rare and carries a poor prognosis. Although there is some literature on primary bladder sarcomatoid urothelial carcinoma, ureteric involvement has been reported infrequently, and this case report describes this unusual histological finding with concurrent divergent squamous differentiation. Despite laparoscopic radical nephroureterectomy, our patient died within six months of diagnosis with local recurrence and metastatic spread. A more thorough understanding of this disease process and consideration of standardised guidelines for treatment are needed to improve patient outcomes.