Burn wound sepsis can be due to exogenous or endogenous bacteria. When rare organisms cause infection, exogenous sources are implicated. This sets into motion hospital infection control team searches, which are both exhausting and harassing to patients and staff. This study examines the skin bacteria present at admission and the frequency of endogenous infection in burn patients. Sixty-two patients with burns up to 92% of the total body surface area underwent unburned skin bacterial surveillance on admission and at weekly intervals using RODAC contact plates. Burn wounds were biopsied for quantitative and qualitative analyses. Morphologically dissimilar colonies were isolated and identified using standard gram-positive and gram-negative identification strips (Analytab Products, Inc. [API]). On admission, the patients harboredStaphylococcusspecies, many of which were unusual and virulent strains. Ten of 11 patients with burn wound sepsis were infected with the same organisms cultured from their unburned skin on admission. A subset of patients (14) grew methicillin-resistantStaphylococcus aureusfrom their wounds or other sites. A comparison with admission isolates showed identical susceptibilities. These data suggest skin is an endogenous source of infection in the burned patient.