Patient's preoccupations with perceived defect in appearance or excessive concern about minimal flaws are among diagnostic criteria of body dysmorphic disorder (BDD). Sufferers usually seek cosmetic procedures such as orthodontic treatment. This study was conducted to estimate the prevalence of BDD among a sample of Iranian orthodontic patients. A total of 270 orthodontic patients were evaluated with BDD-YBOCS questionnaire for the diagnosis of BDD. Fifteen patients (5.5%) were screened positive for BDD. BDD was more frequent among females, singles and in younger patients. Most of the BDD patients experienced multiple previous orthodontic evaluations. The relative high prevalence of BDD among orthodontic patients in Iran offers that orthodontists should take psychologically based problems such as BDD into account while evaluating patient's orthodontic problems.