Objective and method: To review problems that brought patients to the medical unit, this study analyzed the service records regarding sex, age, chief complaint and evidence of flood related skin problems. Managerial problems suggested by the participating volunteers have also been collected.Results: During the 5 days of service, chief complaints of 1,556 patients were recorded. Gender ratio (male:female) was rather stable at 1:1.8. Age range was from 1 month to 98 years with an average age at 39.8 years. The 5 highest problems that brought the patients to medical attention were flood related dermatitis (27.6%), upper respiratory tract infection (15.9%), skin and softtissue injury (12.8%), musculoskeletal pain (12.0%) and asking for medication without any obvious symptoms (8.5%). The most common medications that were asked were topical agents for flood related dermatitis and doxycycline for leptospirosis chemoprophylaxis. The percentage of minor injury cases significantly declined after the second day. Problems that the medical unit encountered during the initial day of service were shortage of medical supply and personnel.Conclusion: Flood-related dermatitis, minor skin injury, and common cold are among priority problems that a mobile medical unit after a flood disaster should be prepared to encounter.Background: On November 1st-3rd, 2010, the biggest flood in 10 years, caused by a depression, occurred to Hat Yai city. Immediately after the flood receded, Songklanagarind Hospital provided volunteer medical unit to affected areas for 5 days, from November 3rd-7th.