A prospective, multi-center, observational study involving 1200 patients hospitalized for the treatment of cSSTIs. The study will be conducted at approximately 50 hospitals in the US. Patients who consent to participate in the registry will be enrolled in the registry within 24 hours of initial IV antibiotic therapy for treatment of one or more cSSTI types. Sites will treat patients according to their usual clinical practice. The objective of this registry is to characterize cSSTIs with respect to patient characteristics and describe patient outcomes.