A series of sulphur-linked and carbon-linked lipophilic carhapenems has been prepared and evaluated for antibacterial activity in vitro and in vivo and for affinity for PBP2' of Staphylococcus aureus. Potent activity in vitro against methicillin-resistant S. aureus and methicillin-resistant coagulase negative staphylococci was observed despite IC5o values for PBP2' being higher than the MIC.