This chapter gives an overview about: resistant organisms in the intensive care units (ICUs); Clostridium difficile in the ICU; strategies of antimicrobial stewardship programmes in ICUs; antibiotic care bundles (ACBs); ASP-driven drug level monitoring of vancomycin and aminoglycosides; antibiotic dose optimization - ASP pharmacokinetic consultations in the ICU; prospective audit, feedback, and de-escalation; intravenous to oral conversion of antibiotics; role of procalcitonin; antibiotic rotation in the ICU; optimization of antibiotics by ASPs in specific situations for ICU patients; antibiotic dosing in renal replacement therapy; transplant patients and the role of antibiotic stewardship; catheter-associated urinary tract infections (CAUTIs); surgical site infection and antibiotic stewardship.