OBJECTIVE To evaluate the diagnostic efficacy of fine needle aspiration cytology (FNAC) in gallbladder mass lesions and to explore the possibility of overlooking malignancy in coexistent adenocarcinoma with xanthogranulomatous cholecystitis (XGC) on fine needle aspiration smears. METHODS In a retrospective, seven-year study, ultrasound-guided needle aspirates from 25 histologically proven cases of gallbladder adenocarcinoma, 11 cases of gallbladder adenocarcinoma associated with XGC and 20 cases of XGC were evaluated for the presence of mesotheliumlike, foam, inflammatory and multinucleate giant cells; pink, granular background; bile; and degenerated cells, along with atypical or frankly malignant cells. Detailed clinical findings were retrieved from the records. RESULTS The overall sensitivity of detecting carcinoma was 90.63% and specificity 94.74%. The sensitivity of detecting malignancy was 80% when adenocarcinoma was associated with XGC. CONCLUSIONS FNAC plays an important role in making the preoperative diagnosis of adenocarcinoma, XGC and coexistent lesions. The probability of detecting malignancy is greater than with XGC in coexistent lesions. Thus, a preoperative FNAC diagnosis would help in determining the urgency of treatment and in planning for the surgical procedure in gallbladder lesions.