Mesothelioma was diagnosed in 33 dogs based on cytological examination of clinical samples which accounted to an incidence of 0.59% of the total tumours diagnosed during the period. The highest incidence of mesothelioma was recorded in Labrador and non-descript breeds, males, and dogs of age group 5-10 years in breed, sex and age wise analysis of tumour incidence. 22(66.67%) cases of mesothelioma were diagnosed in pleural effusions and 11(33.33%) cases were diagnosed from pericardial effusion. Cytologically clusters of hyperchromic round to polygonal neoplastic cells containing round to oval nuclei, prominent nucleoli along with marked anisocytosis, anisokaryosis, increased nuclear-to-cytoplasmic (N:C) ratio, basophilic cytoplasm, binucleation and multinucleation were observed which was diagnostic of mesothelioma.