The incidence of Addison’s disease (AD) is rare. One of the most common causes of AD in developed countries is autoimmune. On the other hand, in developing countries, infective causes still predominate. The symptoms are mostly insidious in onset and non-specific, making it challenging to diagnose AD. The delay in starting the right treatment predisposes to high mortality due to Addison’s crisis. Hence, biochemical parameters play a vital role in diagnosing AD since they usually will present with prominent hyponatraemia, hyperkalaemia and hypoglycaemia. Here, we report a case of a 66-year-old man with multiple co-morbidities and disseminated histoplasmosis who presented with asymptomatic hyponatraemia and hyperkalaemia and was eventually diagnosed with Addison’s disease. Although the non-specific symptoms from his multiple co-morbidities obscured the diagnosis of AD, comprehensive biochemical tests have helped in establishing the diagnosis.