This article covers the diagnosis and treatment of skin and soft tissue infections commonly encountered in the emergency department: impetigo, cutaneous abscesses, purulent cellulitis, nonpurulent cellulitis, and necrotizing skin and soft tissue infections. Most purulent infections in the United States are caused by methicillin-resistant Staphylococcus aureus. For abscesses, we emphasize the importance of incision and drainage. Nonpurulent infections are usually caused by streptococcal species and initial empiric antibiotics need not cover methicillin-resistant Staphylococcus aureus. For uncommon but potentially lethal necrotizing skin and soft tissue infections, the challenge is rapid diagnosis in the emergency department and prompt surgical exploration and debridement.