Infective endocarditis (IE) is a relatively uncommon disease, but has been challenging to diagnose over the years. With the increasing incidence, variety of causative agents and the resistance of microorganisms towards antibiotics, there is still an occurrence of sudden death due to undiagnosed IE. The most common microorganism causing IE is Staphylococcus aureus. However, there is increasing prevalence of other microorganisms causing IE. This case report highlights a case of sudden death due to IE caused by a rare pathogen, Streptococcus constellatus which belongs to the Streptococcus anginosus group (Milleri group). A study noted the crude incidence of IE in 6 world regions ranged between 1.5 and 11.6 cases per 100,000 people. To date, there has been no previous report on sudden death due to IE caused by Streptococcus constellatus in Malaysia, neither in the forensic nor clinical setting. This case report underlined the characteristics and pathological features of this microorganism. The increasing incidence and variety of causative organisms in IE are important public health issues. It is vital for future studies to examine the risk factors of IE related to Streptococcus constellatus, to enhance better understanding, insight and awareness regarding the course of this disease. This in turn may facilitate preventive measures to avoid morbidity and mortality from this condition.