A study on treatment seeking behavior of dengue hemorrhagic fever (DHF) patients was made from 184 clinically diagnosed patients in three hospitals: Children's Hospital, Bangkok; Suphan Buri Provincial Hospital, Suphan Buri Province and Don Chedi Community Hospital in the district of Don Chedi, Suphan Buri Province. The information was collected by interviewing the patients' caretakers while they were attending the patients in the hospitals, using a series of closed- and open-ended questions. Based on the first place of treatment, five patterns of treatment seeking behavior were identified, the most common one was using the clinic as the first step. Different patterns of treatment seeking behavior had the impact on the duration of illness, the number of steps in seeking treatment and the direct patient costs. The socio-demographic characteristics of the patient's caretaker that influenced the decision making to take treatment alternatives included the level of education, occupation, residential area and lay symptom assessment. In addition, economic factors: the capability to reimburse the cost of treatment, the family income and the financial sources, were also important for caretakers to take into consideration when making treatment choices.