Amblyopia is the most common cause of poor vision among individuals under the age of 45 and its prevalence varies in populations. This study was performed to measure the prevalence and causes of amblyopia by ophthalmologists and optometrists in kindergartens of Khuzestan province which were under the supervision of the Department of Welfare (Sazman-e- Behzisti). The inclusion criteria for amblyopia was that the patient had to have visual acuity of 8/10 or less, or have difference of two or more lines of Snellen Chart between two years. Results showed that among 20858 subjects, 215 (1.03%) had amblyopia, 110 were boys (51.2%) and 105 for girls (45.8%). The etiology of 70.2% of cases was refractive errors and in another 21% was strabismus. The remaining cases had different causes. Because the most common cause of amblyopia is refractive errors, which may be asymptomatic, it is recommended that screening of children to be performed for refractive errors and amblyopia in early life.