Background:Tympanic membrane perforation because of CSOM is one amongst the most common causes of hearing loss. This study is done to evaluate hearing loss in patients depending on duration, site & size of perforation.Methods:This Study is done in patients with unilateral inactive mucosal CSOM. Detailed history and thorough ENT examination is done where duration, size and site of perforation is noted. Further the Size of perforation is classified into four groups depending on number of quadrants involved and the site of perforation is categorized into four groups on basis of its relation to handle of malleus, finally hearing evaluation is done by pure tone audiometry and analysed.Result:50 patients belonging to age group of 15-80 years are included, 50% males and 50% females. The duration of perforation is <1 year in 30%, 1-5 years in 42% and >5 years in 28% individuals, in this the hearing loss increases with increasing duration of perforation. Site of perforation is anterior in 34%, posterior in 20%, inferior in 30% and subtotal in 16%, in this posterior quadrant perforation showed maximum hearing loss. Perforation size involving one quadrant is seen in 18%, 2 quadrants in 66% and 4 quadrants in 16% individuals, Single quadrant perforation shows less hearing loss as compared to others.Conclusion:Thus, we conclude that in our study that hearing loss at all the frequencies increases as duration of disease increase and this difference is statistically significant. Here we also conclude that hearing loss increases with increasing size of perforation and the location of tympanic membrane perforation plays a significant role in assessing hearing loss.