Fine Needle Aspiration Cytology (FNAC) is a diagnostic procedure which is yet to grow routes under field conditions in veterinary medicine. Present report deals with a case of 5.5 years-old male Bull Mastiff dog presented at Department of Veterinary Pathology, College of Veterinary Science & Animal Husbandry – Anand, Gujarat with a history of swollen lymph nodes over a period of more than last 3 months. Clinical examination revealed firm growth on pre-scapular as well as popliteal lymph nodes. Other clinical parameters as well as haematobiochemical parameters were within normal range. With dog-owner’s consent, diagnostic FNAC was carried out with aseptic precautions. The case was confirmed as lymphoblastic lymphoma based on microscopic examination of lymph node aspirates stained with Wright’s stain. Owners were counseled regarding the prognosis. Diagnostic significance of FNAC for lymphoblastic lymphoma has been discussed form available literature as a case-based approach. It is concluded that FNAC provides an easy determination of lymphoblastic lymphoma in dog.Diagnosis