Background
Chronic suppurative otitis media (CSOM) is assumed to be a complication of acute otitis media (AOM), but the risk factors for CSOM are not clear. Objectives 1. To study the aetiological organisms for CSOM. 2. To identify the effect of demographic factors on disease manifestation.

Method 
This retrospective study included a case series of 234 patients who had been admitted to National Hospital of Sri Lanka (NHSL), with the complaint of ear discharge and from whom the specimens were sent for microscopy and culture at Department Of Microbiology, NHSL. The period of analysis was 1 year extending from 1 January 2009 to 31 December 2009.Consecutive patients who fulfilled the inclusion criteria were recruited to the retrospective analysis.

Results
Among 234 patients studied, 129 (55.1%) were male and 150 (64.1%) were under 40 yrs old. The mean age was 39.5 yrs (range 12 to 60 yrs, SD = 22.6). The mean duration of ear discharge was 1.2 yrs. (range 6 weeks to 20 yrs.)
Pseudomonas species (29.5%) was the commonest microbial organism to cause ear discharge, followed by staphylococcus (20.5%) and coliform (16.7%) species. Among the fungal agents identified, candida was the most common. 23.1% of the cultures did not reveal any microbiological agent. Eighteen patients (8%) had a prior history of trauma to affected ear and 51 patients (21.8%) were diagnosed with diabetes mellitus.

Conclusion
The commonest microbial agent impicated in CSOM was pseudomonas species followed by staphylococci and coliforms. Demographic variables such as gender or age did not seem to affect the disease manifestation significantly, though CSOM was less common among older people and women.