Core needle biopsy (CNB) is considered to have similar results with open biopsy in accuracy and already becomes a routine procedure to establish the diagnosis of musculoskeletal lesion. However, the accuracy of CNB for muskuloskeletal lesion in Indonesia has not been reported. The aims of the study to know the accuracy of CNB for muskuloskeletal tumor diagnoses. From January 2011 to August 2015, all patients with musculoskeletal lesion in dr. Cipto Mangunkusumo Hospital underwent CNB and subsequently, tumour excision were indentified and enrolled. Diagnostic accuracy was evaluated for both histopathology and clinicopathological conference (CPC) conclusion. A total of 86 samples were enrolled in this study. The accuracy of CNB compared to post excision histopathology is 74.4%. With CPC conclusion, the accuracy is 83.7% with sensitivity 98%, specificity 59% (p<0.001). The accuracy of CNB after immunohistochemistry was increased from 74.4% to 84.9% with sensitivity 98%. The accuracy of CNB was 97.1% and 82.7% for benign lesion and malignant lesion respectively (p<0.01). The accuracy of CNB to differ and to confirm diagnosis as primary or metastatic lesion was 97.2% and 85.7% respectively (p<0.001). Inconclusion, CNB is a reliable diagnostic method to establish musculoskeletal tumor diagnoses. CPC significantly provides better accuracy rate of CNB.