Leptospirosis is a common zoonosis that is endemic in the tropical Top End of the Northern Territory. Disease ranges from mild to very severe. We report a patient with anicteric leptospirosis who became critically ill, challenging the view that anicteric leptospirosis is less severe than the icteric form. Despite a typical but non-specific presentation and recreational high-risk activities, diagnosis of leptospirosis was delayed. The patient developed respiratory failure, resulting from pulmonary haemorrhage, and acute renal failure. This case highlights the multiple factors that should prompt health care workers to consider the diagnosis of leptospirosis in non-classical presentations.