Objective: To document a case of azathioprine hepatotoxicity confirmed by rechallenge. Clinical features: A 50-year-old female with nodular scleritis of her left eye was treated with azathioprine as a steroid sparing agent. Agent four weeks liver transaminase concentrations increased and azathioprine was ceased. Azathioprine was recommenced after liver enzymes normalised. Signs and symptoms of hepatotoxicity recurred within 3 days and resolved rapidly after cessation of azathioprine. Conclusion: Azathioprine rechallenge in a patient who has experienced initial hepatotoxicity may lead to recurrence which is potentially more severe.