This chapter discusses chronic suppurative otitis media (CSOM), which means chronic or long-standing infection of the middle ear cleft which is characterised by discharge, deafness and a perforation of the tympanic membrane. Examination of ear canal shows a perforation of tympanic membrane which is central with variable shape and size, dry or wet, mucosa of the middle ear may be polypoidal, oedematous or congested depending upon the stage of CSOM. Hearing is better when ear is discharging due to shielding effect of round window or discharge covering the perforation. Antibiotics play an important role and are given depending upon culture and sensitivity report of discharge. Presence of keratinising stratified squamous epithelium within the middle ear cleft constitutes cholesteatoma. X-ray both mastoid lateral oblique view may show sclerosis, destruction or cavitations only when it is extensive disease. Negative intratympanic pressure results in the formation of retraction pockets involving attic or posterosuperior tympanic segment.