In the present study it was found that incidence of occurrence of skin neoplasms was the highest (42.64%) among dog population in and around Kolkata, India which was followed by neoplasms in venereal organs (23.54%), mammary glands of bitches (20.58%) and other gastrointestinal organs (13.24) respectively. Based on gross and histopathological studies skin neoplasms were mainly composed of fibrosarcoma, hemangiosarcoma, squamous cell carcinoma, basal cell epithelioma, sebaceous adenoma, perianal adenoma and adenocarcinoma of sebaceous glands. Gross and histopathological studies of neoplasms of mammary gland revealed that the neoplasms were mostly of adenocarcinoma cystic papillary form, mixed mammary carcinoma, cystic papillary form, adenocarcinoma infiltrating type, adenocarcinoma tubular type, mixed mammary tumor and fibroadenoma. Canine transmissible venereal tumors were seen mostly in Alsatian and mongrel bitches. The lymphosarcoma was the predominant venereal neoplasm which is located as nodular growth in the inner surface of vaginal wall in bitches. There was bleeding from the growth. Disease was found to be predominant in 4-12 years age group of dogs.