On 26 December 2004, a tsunami devastated the west coast of Thailand and caused 8457 injuries and 5395 deaths. Data were collected from 26 December 2004 to 31 January 2005 at four public hospitals to describe the character and treatment of wounds of 523 persons who were injured during tsunami and sought medical treatment. Wounds were contaminated with mud, sand, debris and sea water and had an infection rate of 66.5% (674/1013). Most wounds (45%) had poly-microbial infection with gram-negative rods such as Escherichia coli, Klebsiella pneumoniae, Proteus and Pseudomonas species. The risk of wound infection increased with size of the wound and presence of an open fracture. Infections occurred more frequently on the lower than upper trunk of the body. Early treatment with antibiotics was protective against wound infection. Many patients asked to have their wounds sutured so that they could return to their village to look for their families and to repair damage. This report suggests that wounds should be aggressively debrided and suturing postponed if possible. Patients should be given broad spectrum antibiotics to assist with wound healing.