Introduction:Invasive meningococcal disease can be difficult to detect early in its course when patients may appear well and the severity of their illness is obscured by non-specific complaints.Case presentation:We report five cases of meningococcal sepsis in adult patients who presented to an emergency department early in the course of their disease, but whose severity of illness was not recognized.Conclusion:Suspicion of meningococcal sepsis should be heightened in the setting of hypotension, tachycardia, elevated shock index, leukopaenia with left shift, thrombocytopaenia and hypokalaemia, prompting early sepsis care.