BACKGROUND: Recurrence and side effects of current treatments for urolithiasis confine their application, so other options using traditional herbal therapy are being sought. OBJECTIVES: In this experimental study we have tried to evaluate the antilithiatic effects of herbal extraxt of Tribulus terrestris which is often used to treat different kinds of urinary diseases such as urolithiasis in human on cats. METHODS: To evaluate the therapeutic effect of plant, the hydro alcoholic extract of T.terrestris was assessed for activity against induced urolithiasis in cats. The extract of such herb was administered at daily oral doses of 200 mg/kg for 30 days. RESULTS: Microscopic analysis of urine sediments and ultrasonographic study of kidneys and urinary bladder confirmed inhibition of crystal formation in tested cats. CONCLUSIONS: Our results indicate this herbal extract could be a potential candidate for prevention of urolithiasis in cats. Further studies are needed to clarify the precise anti-crystallization mechanism of T.terrestris in cats.