Bone neoplasms are rarely found; however, they usually occur in young patients. It is imperative to diagnose these conditions promptly and accurately, as patient’s outcomes also depend on timely and appropriate treatments. Fine Needle Aspiration Biopsy (FNAB) is increasingly utilized as a method of establishing preoperative diagnosis of bone tumors because it is less invasive, rapid, and cost-effective. This study aims to determine the diagnostic value of the presence of certain cytological features in FNAB for bone tumors, evaluate cytological features to differentiate between benign and malignant bone tumors, and determine the cut-off point of the presence of certain cytological features of FNAB in bone tumors. This study is an analytical cross-sectional study to 35 bone tumor cases which underwent FNAB and subsequent histopathological examination from January 2014 – December 2017 in the Department of Anatomic Pathology of Saiful Anwar General Hospital. Diagnostic value testing was performed using 2x2 table and Receiver Operating Characteristic (ROC) curve to determine the sensitivity, specificity, and accuracy of FNAB by evaluating cytological features of anaplasia in differentiating between benign and malignant bone tumors in comparation to histopathological examination. The result revealed that the presence of >4 cytological features of anaplasia without the presence of clinicoradiological data yield 81.82% sensitivity, 100% specificity, 100% positive predictive value, 76.47% negative predictive value, and 88.57% accuracy. In conclusion, cytological features of anaplasia could become a reliable predictor in determining benignity and malignancy of bone tumors especially in cases where clinicoradiological data are insufficient.