The antibiotic treatment of severe sepsis poses an increasing challenge in ICU. The multidrug resistance and diverse pharmacokinetics of antibiotics requires a different approach on antibiotic therapy because of the inadequate serum antibiotic levels found in ICU patients. The current guidelines or recommendations of antibiotic treatment take into account the pharmacokinetic parameters in determining the proper dosage. The recommended antibiotic treatment of severe sepsis requires daily assessment and dosage adjustment based on measurements of antibiotic concentrations in order to optimize the treatment.