<p class="abstract"><strong>Background:</strong> This was a comparative microbial study of pre and postoperative mastoidectomy. The aim of the present study was to evaluate various causes responsible for discharging mastoid cavity.</p><p class="abstract"><strong>Methods:</strong> Total of 160 patients of which 100 cases were of preoperative group and 60 cases were postoperative group included in the study.  </p><p class="abstract"><strong>Results:</strong> Mono infection was seen in 95% and 86.7% in pre and postoperative cases respectively; where as 5% of preoperative and 13.3% of postoperative cases were diinfections. <em>Pseudomonas</em> (32%) was found in highest number followed by <em>Staphylococcus aureus</em> (16%), <em>Klebsiella spp</em>. (16%), <em>Escherichia coli</em> (15%), <em>Proteus mirabilis</em> (14%), <em>Aspergillus fumigatus</em> (2%), <em>Candida</em> (1%), and <em>Cladosporium</em> (1%) in preoperative cases. In postoperative cases, 46.7% of <em>Pseudomonas spp</em>, followed by 16.5% <em>Staphylococcus</em>, 16.7% <em>Klebsiella spp</em>, 11.7% <em>Proteus mirabilis</em>, 10% <em>Escherichia coli</em>, 8.3% <em>Aspergillus fumigatus</em> and 5% <em>Candida</em> were isolated.</p><p><strong>Conclusions:</strong> Multiple factors were responsible for otorhhoea with significant contribution from the microbes.</p>