Septic shock is still a lethal disease in intensive care units (ICU). The mortality can exceed 40% even with therapeutic management. The high mortality is clearly associated with the delay of appropriate antimicrobial therapy. Early diagnosis and identification of infectious source is the mainstay of optimal therapeutic management. On the other hand, source control and optimize antibiotic dosing according to pharmacokinetics (PK)/pharmacodynamics (PD) properties of antibiotics and organ dysfunction of patients are required to get the best clinical outcome.