Introduction: A “hearing-impaired is defined as abnormal or reduced function in hearing resulting from auditory disorder” (Stach,1997). The goal of any preschool and school screening program should be to accurately identify those children whose hearing has impaired resulting from either conductive and / or sensory - neural pathology. Although some ear pathologies (e.g., middle ear effusion) might not produce a significant hearing loss, screening for these pathologies should be a part of the screening program because they may influence the potential to learn. Materials & Method: This research was carried out in a cross-sectional descriptive study on 577 children (278 girls and 299 boys) among the 3-6 years old children of kindergartens in Welfare Organization of the Tehran Province from March to June 2001. The otoscopy examination, pure-tone screening and impedance screening was conducted after completion the parents awareness form of the hearing loss existence.

Results: In this study, there were 12.58% abnormal conditions of external ear canal, 23.7% abnormal tympanic membrane, 34.3% abnormal tympanograms, 35% no acoustic reflex, 12.6% hearing loss including 9.7% bilateral and 2.9% unilateral hearing loss (12.0% conductive hearing loss, 0.64% sensory-neural hearing loss and 0.36% mixed hearing loss), higher prevalence of left ear disorders and statistically meaning difference between two ears (P<0.05) in all of studied items, except of acoustic reflex condition.

Conclusion: With respect to high prevalence of need to medical care and the negative effects of middle ear disorders in learning of preschool children, and also due to the importance of early identification and intervention of hearing loss in aural rehabilitation programs, awaring and teaching the people about the effects of hearing disorders and it's prevention and identification are very important.