The present study was conducted on 24 cases of canine mammary tumour (CMT) to evaluate cytology versus histopathology in its diagnosis. During surgical intervention samples were taken for cytology and histopathology by using FNAB and excisional biopsy respectively. The tumours were also sub-classified and graded on the basis of histopathology. On the basis of cytology all the tumours were found to be malignant which was confirmed by histopathology. A comparison of cytology and histopathology revealed a cent-percent positive correlation in detecting malignancy and tumour sub-type. However, there was poor correlation between cytology and histopathology in predicting the grade and stage of malignancy.